{"id":91,"date":"2026-09-18T10:50:46","date_gmt":"2026-09-18T02:50:46","guid":{"rendered":"https:\/\/decagrammaton.xyz\/?p=91"},"modified":"2026-09-18T10:50:47","modified_gmt":"2026-09-18T02:50:47","slug":"010-c%e8%af%ad%e8%a8%80%e5%8a%a8%e6%80%81%e5%86%85%e5%ad%98","status":"publish","type":"post","link":"https:\/\/decagrammaton.xyz\/?p=91","title":{"rendered":"010-C\u8bed\u8a00\u52a8\u6001\u5185\u5b58"},"content":{"rendered":"\n
\n\n\n\n

\u524d\u9762\u6211\u4eec\u5b66\u4e60\u4e86\uff1a<\/p>\n\n\n\n

\u6570\u7ec4\n\u51fd\u6570\n\u6307\u9488\n\u7ed3\u6784\u4f53<\/code><\/pre>\n\n\n\n
\u4e4b\u524d\u521b\u5efa\u53d8\u91cf\u65f6\uff0c\u901a\u5e38\u90fd\u662f\u76f4\u63a5\u5199\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> a;<\/span><\/span>\n<\/a>int<\/span> arr[<\/span>10<\/span>];<\/span><\/span>\n<\/a>struct<\/span> Student s;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8fd9\u4e9b\u53d8\u91cf\u7684\u5927\u5c0f\u901a\u5e38\u5728\u7a0b\u5e8f\u7f16\u8bd1\u65f6\u5c31\u5df2\u7ecf\u786e\u5b9a\u3002<\/p>\n\n\n\n
\u4f46\u662f\u6709\u65f6\u5019\u6211\u4eec\u5e76\u4e0d\u77e5\u9053\u7a0b\u5e8f\u8fd0\u884c\u65f6\u5230\u5e95\u9700\u8981\u591a\u5c11\u5185\u5b58\u3002<\/p>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
\u7528\u6237\u8f93\u5165\u9700\u8981\u4fdd\u5b58\u591a\u5c11\u4e2a\u6574\u6570\uff1f\n\u5b66\u751f\u5230\u5e95\u6709\u591a\u5c11\u4eba\uff1f\n\u6587\u4ef6\u6709\u591a\u5927\uff1f\n\u5b57\u7b26\u4e32\u5230\u5e95\u6709\u591a\u957f\uff1f<\/code><\/pre>\n\n\n\n
\u8fd9\u65f6\u5019\u5c31\u9700\u8981\u4f7f\u7528\uff1a<\/p>\n\n\n\n
\u52a8\u6001\u5185\u5b58\u5206\u914d\u3002<\/strong><\/p>\n\n\n\n
\n\n\n\n
\u4e00\u3001\u4ec0\u4e48\u662f\u52a8\u6001\u5185\u5b58<\/h1>\n\n\n\n
\u666e\u901a\u53d8\u91cf\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> a;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u7a0b\u5e8f\u8fd0\u884c\u65f6\uff0c\u4f1a\u81ea\u52a8\u4e3a a<\/code> \u5206\u914d\u5185\u5b58\u3002<\/p>\n\n\n\n
\u800c\u52a8\u6001\u5185\u5b58\u662f\uff1a<\/p>\n\n\n\n
\u7a0b\u5e8f\u8fd0\u884c\n   \u2193\n\u9700\u8981\u591a\u5c11\u5185\u5b58\n   \u2193\n\u8fd0\u884c\u65f6\u7533\u8bf7\n   \u2193\n\u4f7f\u7528\n   \u2193\n\u4e0d\u9700\u8981\u4e86\n   \u2193\n\u91ca\u653e<\/code><\/pre>\n\n\n\n
\u8fd9\u5c31\u662f\uff1a<\/p>\n\n\n\n
\u52a8\u6001\u5185\u5b58\u5206\u914d\u3002<\/strong><\/p>\n\n\n\n
C \u8bed\u8a00\u4e3b\u8981\u4f7f\u7528\u4e0b\u9762\u51e0\u4e2a\u51fd\u6570\uff1a<\/p>\n\n\n\n
malloc\ncalloc\nrealloc\nfree<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u4e8c\u3001\u6808\u5185\u5b58\u548c\u5806\u5185\u5b58<\/h1>\n\n\n\n
\u5b66\u4e60\u52a8\u6001\u5185\u5b58\u4e4b\u524d\uff0c\u5148\u8ba4\u8bc6\u4e24\u4e2a\u6982\u5ff5\u3002<\/p>\n\n\n\n
\u6808\uff08Stack\uff09<\/h2>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> a =<\/span> 10<\/span>;<\/span><\/span>\n<\/a><\/span>\n<\/a>void<\/span> test()<\/span> {<\/span><\/span>\n<\/a>    int<\/span> x =<\/span> 20<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8fd9\u79cd\u666e\u901a\u5c40\u90e8\u53d8\u91cf\u901a\u5e38\u4f7f\u7528\u6808\u7a7a\u95f4\u3002<\/p>\n\n\n\n
\u53ef\u4ee5\u7b80\u5355\u7406\u89e3\u4e3a\uff1a<\/p>\n\n\n\n
\u8fdb\u5165\u51fd\u6570\n    \u2193\n\u521b\u5efa\u5c40\u90e8\u53d8\u91cf\n    \u2193\n\u4f7f\u7528\n    \u2193\n\u51fd\u6570\u7ed3\u675f\n    \u2193\n\u81ea\u52a8\u91ca\u653e<\/code><\/pre>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>void<\/span> test()<\/span> {<\/span><\/span>\n<\/a>    int<\/span> x =<\/span> 10<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
test()<\/code> \u7ed3\u675f\u540e\uff0cx<\/code> \u5c31\u4e0d\u518d\u5b58\u5728\u3002<\/p>\n\n\n\n
\n\n\n\n
\u4e09\u3001\u5806\uff08Heap\uff09<\/h1>\n\n\n\n
\u52a8\u6001\u7533\u8bf7\u7684\u5185\u5b58\u901a\u5e38\u6765\u81ea\u5806\u3002<\/p>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>));<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u53ef\u4ee5\u7406\u89e3\u6210\uff1a<\/p>\n\n\n\n
\u7a0b\u5e8f\u8fd0\u884c\n   \u2193\nmalloc\n   \u2193\n\u4ece\u5806\u4e2d\u7533\u8bf7\u5185\u5b58\n   \u2193\n\u8fd4\u56de\u5730\u5740\n   \u2193\np \u4fdd\u5b58\u5730\u5740<\/code><\/pre>\n\n\n\n
\u8fd9\u5757\u5185\u5b58\u4e0d\u4f1a\u56e0\u4e3a\u666e\u901a\u51fd\u6570\u7ed3\u675f\u5c31\u81ea\u52a8\u91ca\u653e\u3002<\/p>\n\n\n\n
\u9700\u8981\u624b\u52a8\uff1a<\/p>\n\n\n\n
<\/a>free(<\/span>p);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\n\n\n\n
\u56db\u3001\u4e3a\u4ec0\u4e48\u9700\u8981\u52a8\u6001\u5185\u5b58<\/h1>\n\n\n\n
\u5047\u8bbe\u6211\u4eec\u9700\u8981\u4fdd\u5b58 100 \u4e2a\u6574\u6570\u3002<\/p>\n\n\n\n
\u6700\u7b80\u5355\u7684\u65b9\u6cd5\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> arr[<\/span>100<\/span>];<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4f46\u662f\u5982\u679c\u7528\u6237\u8fd0\u884c\u7a0b\u5e8f\u540e\u8f93\u5165\uff1a<\/p>\n\n\n\n
\u9700\u8981 100000 \u4e2a\u6574\u6570<\/code><\/pre>\n\n\n\n
\u90a3\u4e48\u7a0b\u5e8f\u5c31\u4e0d\u80fd\u7ee7\u7eed\u4f7f\u7528\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> arr[<\/span>100<\/span>];<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u56e0\u4e3a\u5927\u5c0f\u5df2\u7ecf\u5199\u6b7b\u4e86\u3002<\/p>\n\n\n\n
\u53ef\u4ee5\u4f7f\u7528\u52a8\u6001\u5185\u5b58\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> n;<\/span><\/span>\n<\/a><\/span>\n<\/a>scanf(<\/span>\"<\/span>%d<\/span>\"<\/span>,<\/span> &<\/span>n);<\/span><\/span>\n<\/a><\/span>\n<\/a>int<\/span> *<\/span>arr =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>)<\/span> *<\/span> n);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u6b64\u65f6\uff1a<\/p>\n\n\n\n
n = 10\n\u2193\n\u7533\u8bf7 10 \u4e2a int\n\nn = 100\n\u2193\n\u7533\u8bf7 100 \u4e2a int\n\nn = 100000\n\u2193\n\u7533\u8bf7 100000 \u4e2a int<\/code><\/pre>\n\n\n\n
\u8fd9\u5c31\u662f\u52a8\u6001\u5185\u5b58\u7684\u610f\u4e49\u3002<\/p>\n\n\n\n
\n\n\n\n
\u4e94\u3001malloc<\/h1>\n\n\n\n
malloc<\/code> \u662f\u6700\u5e38\u7528\u7684\u52a8\u6001\u5185\u5b58\u5206\u914d\u51fd\u6570\u3002<\/p>\n\n\n\n
\u9700\u8981\uff1a<\/p>\n\n\n\n
<\/a>#include <\/span><stdlib.h><\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u57fa\u672c\u683c\u5f0f\uff1a<\/p>\n\n\n\n
<\/a>malloc(<\/span>\u5b57\u8282\u6570);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>));<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8fd9\u91cc\u7533\u8bf7\u4e86\u8db3\u591f\u5b58\u653e\u4e00\u4e2a int<\/code> \u7684\u5185\u5b58\u3002<\/p>\n\n\n\n
\n\n\n\n
\u516d\u3001malloc \u8fd4\u56de\u4ec0\u4e48<\/h1>\n\n\n\n
\u8fd9\u662f\u6700\u91cd\u8981\u7684\u5730\u65b9\u4e4b\u4e00\u3002<\/p>\n\n\n\n
<\/a>malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>))<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8fd4\u56de\u7684\u662f\uff1a<\/p>\n\n\n\n
\u8fd9\u5757\u5185\u5b58\u7684\u5730\u5740\u3002<\/strong><\/p>\n\n\n\n
\u6240\u4ee5\u53ef\u4ee5\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>));<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4e5f\u5c31\u662f\uff1a<\/p>\n\n\n\n
malloc\n  \u2193\n\u7533\u8bf7\u5185\u5b58\n  \u2193\n\u5f97\u5230\u5730\u5740\n  \u2193\np \u4fdd\u5b58\u5730\u5740<\/code><\/pre>\n\n\n\n
\u53ef\u4ee5\u7406\u89e3\u6210\uff1a<\/p>\n\n\n\n
p\n\u2193\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510\n\u2502 int \u5185\u5b58 \u2502\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u4e03\u3001malloc + sizeof<\/h1>\n\n\n\n
\u4e0d\u8981\u76f4\u63a5\u5047\u8bbe int<\/code> \u4e00\u5b9a\u662f 4 \u5b57\u8282\u3002<\/p>\n\n\n\n
\u63a8\u8350\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>));<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u800c\u4e0d\u662f\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>4<\/span>);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u56e0\u4e3a\uff1a<\/p>\n\n\n\n
<\/a>sizeof<\/span>(<\/span>int<\/span>)<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4f1a\u81ea\u52a8\u5f97\u5230\u5f53\u524d\u5e73\u53f0\u7684 int<\/code> \u5927\u5c0f\u3002<\/p>\n\n\n\n
\n\n\n\n
\u516b\u3001\u7533\u8bf7\u591a\u4e2a\u5143\u7d20<\/h1>\n\n\n\n
\u4f8b\u5982\u7533\u8bf7 10 \u4e2a int<\/code>\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>)<\/span> *<\/span> 10<\/span>);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u53ef\u4ee5\u7406\u89e3\u6210\uff1a<\/p>\n\n\n\n
p\n\u2193\n\u250c\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u2510\n\u2502int \u2502int \u2502int \u2502int \u2502int \u2502int \u2502int \u2502int \u2502int \u2502int \u2502\n\u2514\u2500\u2500\u2500\u2500\u2534\u2500\u2500\u2500\u2500\u2534\u2500\u2500\u2500\u2500\u2534\u2500\u2500\u2500\u2500\u2534\u2500\u2500\u2500\u2500\u2534\u2500\u2500\u2500\u2500\u2534\u2500\u2500\u2500\u2500\u2534\u2500\u2500\u2500\u2500\u2534\u2500\u2500\u2500\u2500\u2534\u2500\u2500\u2500\u2500\u2518<\/code><\/pre>\n\n\n\n
\u8fd9\u548c\u6570\u7ec4\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> arr[<\/span>10<\/span>];<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5728\u4f7f\u7528\u4e0a\u6709\u5f88\u591a\u76f8\u4f3c\u4e4b\u5904\u3002<\/p>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>p[<\/span>0<\/span>]<\/span> =<\/span> 10<\/span>;<\/span><\/span>\n<\/a>p[<\/span>1<\/span>]<\/span> =<\/span> 20<\/span>;<\/span><\/span>\n<\/a>p[<\/span>2<\/span>]<\/span> =<\/span> 30<\/span>;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\n\n\n\n
\u4e5d\u3001\u52a8\u6001\u6570\u7ec4<\/h1>\n\n\n\n
\u4e00\u4e2a\u5b8c\u6574\u4f8b\u5b50\uff1a<\/p>\n\n\n\n
<\/a>#include <\/span><stdio.h><\/span><\/span>\n<\/a>#include <\/span><stdlib.h><\/span><\/span>\n<\/a><\/span>\n<\/a>int<\/span> main()<\/span> {<\/span><\/span>\n<\/a>    int<\/span> n;<\/span><\/span>\n<\/a><\/span>\n<\/a>    printf(<\/span>\"\u8bf7\u8f93\u5165\u6570\u91cf: \"<\/span>);<\/span><\/span>\n<\/a>    scanf(<\/span>\"<\/span>%d<\/span>\"<\/span>,<\/span> &<\/span>n);<\/span><\/span>\n<\/a><\/span>\n<\/a>    int<\/span> *<\/span>arr =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>)<\/span> *<\/span> n);<\/span><\/span>\n<\/a><\/span>\n<\/a>    for<\/span> (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i <<\/span> n;<\/span> i++)<\/span> {<\/span><\/span>\n<\/a>        arr[<\/span>i]<\/span> =<\/span> i +<\/span> 1<\/span>;<\/span><\/span>\n<\/a>    }<\/span><\/span>\n<\/a><\/span>\n<\/a>    for<\/span> (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i <<\/span> n;<\/span> i++)<\/span> {<\/span><\/span>\n<\/a>        printf(<\/span>\"<\/span>%d<\/span> \"<\/span>,<\/span> arr[<\/span>i]);<\/span><\/span>\n<\/a>    }<\/span><\/span>\n<\/a><\/span>\n<\/a>    free(<\/span>arr);<\/span><\/span>\n<\/a><\/span>\n<\/a>    return<\/span> 0<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4f8b\u5982\u8f93\u5165\uff1a<\/p>\n\n\n\n
5<\/code><\/pre>\n\n\n\n
\u8f93\u51fa\uff1a<\/p>\n\n\n\n
1 2 3 4 5<\/code><\/pre>\n\n\n\n
\u8fd9\u91cc\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>arr =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>)<\/span> *<\/span> n);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5c31\u521b\u5efa\u4e86\u4e00\u4e2a\u8fd0\u884c\u65f6\u51b3\u5b9a\u5927\u5c0f\u7684\u201c\u6570\u7ec4\u201d\u3002<\/p>\n\n\n\n
\n\n\n\n
\u5341\u3001malloc \u7533\u8bf7\u5931\u8d25<\/h1>\n\n\n\n
malloc<\/code> \u4e0d\u4e00\u5b9a\u603b\u80fd\u6210\u529f\u3002<\/p>\n\n\n\n
\u5982\u679c\u7533\u8bf7\u5931\u8d25\uff0c\u5b83\u4f1a\u8fd4\u56de\uff1a<\/p>\n\n\n\n
<\/a>NULL<\/span><\/code><\/pre><\/div>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>)<\/span> *<\/span> 100<\/span>);<\/span><\/span>\n<\/a><\/span>\n<\/a>if<\/span> (<\/span>p ==<\/span> NULL)<\/span> {<\/span><\/span>\n<\/a>    printf(<\/span>\"\u5185\u5b58\u7533\u8bf7\u5931\u8d25<\/span>\\n<\/span>\"<\/span>);<\/span><\/span>\n<\/a>    return<\/span> 1<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u56e0\u6b64\u63a8\u8350\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>));<\/span><\/span>\n<\/a><\/span>\n<\/a>if<\/span> (<\/span>p ==<\/span> NULL)<\/span> {<\/span><\/span>\n<\/a>    printf(<\/span>\"malloc failed<\/span>\\n<\/span>\"<\/span>);<\/span><\/span>\n<\/a>    return<\/span> 1<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\n\n\n\n
\u5341\u4e00\u3001NULL \u662f\u4ec0\u4e48<\/h1>\n\n\n\n
NULL<\/code> \u53ef\u4ee5\u7406\u89e3\u4e3a\uff1a<\/p>\n\n\n\n
\u7a7a\u6307\u9488\u3002<\/strong><\/p>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> NULL;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8868\u793a\uff1a<\/p>\n\n\n\n
p \u76ee\u524d\u6ca1\u6709\u6307\u5411\u6709\u6548\u5bf9\u8c61<\/code><\/pre>\n\n\n\n
\u6240\u4ee5\u5728\u4f7f\u7528 malloc<\/code> \u540e\uff0c\u7ecf\u5e38\u5199\uff1a<\/p>\n\n\n\n
<\/a>if<\/span> (<\/span>p ==<\/span> NULL)<\/span> {<\/span><\/span>\n<\/a>    ...<\/span><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u68c0\u67e5\u7533\u8bf7\u662f\u5426\u6210\u529f\u3002<\/p>\n\n\n\n
\n\n\n\n
\u5341\u4e8c\u3001\u4f7f\u7528\u52a8\u6001\u5185\u5b58<\/h1>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>));<\/span><\/span>\n<\/a><\/span>\n<\/a>if<\/span> (<\/span>p ==<\/span> NULL)<\/span> {<\/span><\/span>\n<\/a>    return<\/span> 1<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span>\n<\/a><\/span>\n<\/a>*<\/span>p =<\/span> 100<\/span>;<\/span><\/span>\n<\/a><\/span>\n<\/a>printf(<\/span>\"<\/span>%d\\n<\/span>\"<\/span>,<\/span> *<\/span>p);<\/span><\/span>\n<\/a><\/span>\n<\/a>free(<\/span>p);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8fd9\u91cc\u628a\u4e4b\u524d\u5b66\u7684\u6307\u9488\u5168\u90e8\u4e32\u8d77\u6765\u4e86\u3002<\/p>\n\n\n\n
\n\n\n\n
\u5341\u4e09\u3001malloc \u7684\u5b8c\u6574\u6d41\u7a0b<\/h1>\n\n\n\n
\u52a8\u6001\u5185\u5b58\u6700\u91cd\u8981\u7684\u6d41\u7a0b\uff1a<\/p>\n\n\n\n
\u7533\u8bf7\n \u2193\nmalloc\n \u2193\n\u68c0\u67e5 NULL\n \u2193\n\u4f7f\u7528\n \u2193\nfree<\/code><\/pre>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>));<\/span><\/span>\n<\/a><\/span>\n<\/a>if<\/span> (<\/span>p ==<\/span> NULL)<\/span> {<\/span><\/span>\n<\/a>    return<\/span> 1<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span>\n<\/a><\/span>\n<\/a>*<\/span>p =<\/span> 100<\/span>;<\/span><\/span>\n<\/a><\/span>\n<\/a>printf(<\/span>\"<\/span>%d\\n<\/span>\"<\/span>,<\/span> *<\/span>p);<\/span><\/span>\n<\/a><\/span>\n<\/a>free(<\/span>p);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u53ef\u4ee5\u8bb0\u6210\uff1a<\/p>\n\n\n\n
malloc \u2192 \u4f7f\u7528 \u2192 free<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u5341\u56db\u3001free<\/h1>\n\n\n\n
\u7533\u8bf7\u4e86\u52a8\u6001\u5185\u5b58\u4ee5\u540e\uff0c\u4f7f\u7528\u7ed3\u675f\u5c31\u9700\u8981\u91ca\u653e\uff1a<\/p>\n\n\n\n
<\/a>free(<\/span>p);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>));<\/span><\/span>\n<\/a><\/span>\n<\/a>*<\/span>p =<\/span> 100<\/span>;<\/span><\/span>\n<\/a><\/span>\n<\/a>printf(<\/span>\"<\/span>%d\\n<\/span>\"<\/span>,<\/span> *<\/span>p);<\/span><\/span>\n<\/a><\/span>\n<\/a>free(<\/span>p);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
free()<\/code> \u7684\u4f5c\u7528\uff1a<\/p>\n\n\n\n
\u91ca\u653e\u4e4b\u524d\u52a8\u6001\u7533\u8bf7\u7684\u90a3\u5757\u5185\u5b58\u3002<\/strong><\/p>\n\n\n\n
\n\n\n\n
\u5341\u4e94\u3001\u4e3a\u4ec0\u4e48\u9700\u8981 free<\/h1>\n\n\n\n
\u5047\u8bbe\uff1a<\/p>\n\n\n\n
<\/a>void<\/span> test()<\/span> {<\/span><\/span>\n<\/a>    int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>)<\/span> *<\/span> 1000<\/span>);<\/span><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u51fd\u6570\u7ed3\u675f\u4ee5\u540e\uff1a<\/p>\n\n\n\n
p \u8fd9\u4e2a\u6307\u9488\u53d8\u91cf\u6d88\u5931<\/code><\/pre>\n\n\n\n
\u4f46\u662f\uff1a<\/p>\n\n\n\n
malloc \u5f97\u5230\u7684\u5806\u5185\u5b58<\/code><\/pre>\n\n\n\n
\u4ecd\u7136\u53ef\u80fd\u6ca1\u6709\u88ab\u91ca\u653e\u3002<\/p>\n\n\n\n
\u8fd9\u5c31\u4ea7\u751f\u4e86\uff1a<\/p>\n\n\n\n
\u5185\u5b58\u6cc4\u6f0f\u3002<\/strong><\/p>\n\n\n\n
\n\n\n\n
\u5341\u516d\u3001\u5185\u5b58\u6cc4\u6f0f<\/h1>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>));<\/span><\/span>\n<\/a><\/span>\n<\/a>p =<\/span> NULL;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8fd9\u91cc\u539f\u6765\u7684\u5730\u5740\u4e22\u6389\u4e86\u3002<\/p>\n\n\n\n
\u53d8\u6210\uff1a<\/p>\n\n\n\n
malloc\n \u2193\n\u4e00\u5757\u5185\u5b58\n \u2193\np \u6307\u5411\u5b83\n\np = NULL\n\n\u539f\u6765\u7684\u5730\u5740\u4e22\u5931\n \u2193\n\u6ca1\u4eba\u80fd\u627e\u5230\u8fd9\u5757\u5185\u5b58<\/code><\/pre>\n\n\n\n
\u8fd9\u5c31\u662f\u5178\u578b\u7684\u5185\u5b58\u6cc4\u6f0f\u3002<\/p>\n\n\n\n
\u6b63\u786e\u65b9\u5f0f\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>));<\/span><\/span>\n<\/a><\/span>\n<\/a>free(<\/span>p);<\/span><\/span>\n<\/a><\/span>\n<\/a>p =<\/span> NULL;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\n\n\n\n
\u5341\u4e03\u3001free \u540e\u6307\u9488\u4f1a\u600e\u6837<\/h1>\n\n\n\n
\u770b\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>));<\/span><\/span>\n<\/a><\/span>\n<\/a>*<\/span>p =<\/span> 100<\/span>;<\/span><\/span>\n<\/a><\/span>\n<\/a>free(<\/span>p);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u6ce8\u610f\uff1a<\/p>\n\n\n\n
free(p)<\/code><\/pre>\n\n\n\n
\u91ca\u653e\u7684\u662f\uff1a<\/p>\n\n\n\n
p \u6307\u5411\u7684\u5185\u5b58\u3002<\/strong><\/p>\n\n\n\n
\u5e76\u4e0d\u662f\u8ba9\uff1a<\/p>\n\n\n\n
p<\/code><\/pre>\n\n\n\n
\u8fd9\u4e2a\u6307\u9488\u53d8\u91cf\u81ea\u52a8\u53d8\u6210 NULL<\/code>\u3002<\/p>\n\n\n\n
\u6240\u4ee5 p<\/code> \u53ef\u80fd\u4ecd\u7136\u4fdd\u5b58\u7740\u539f\u6765\u7684\u5730\u5740\u3002<\/p>\n\n\n\n
\n\n\n\n
\u5341\u516b\u3001\u91ce\u6307\u9488 \/ \u60ac\u7a7a\u6307\u9488<\/h1>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>));<\/span><\/span>\n<\/a><\/span>\n<\/a>*<\/span>p =<\/span> 100<\/span>;<\/span><\/span>\n<\/a><\/span>\n<\/a>free(<\/span>p);<\/span><\/span>\n<\/a><\/span>\n<\/a>printf(<\/span>\"<\/span>%d\\n<\/span>\"<\/span>,<\/span> *<\/span>p);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8fd9\u662f\u9519\u8bef\u7684\u3002<\/p>\n\n\n\n
\u56e0\u4e3a\uff1a<\/p>\n\n\n\n
p\n \u2193\n\u539f\u6765\u7684\u5185\u5b58\n \u2193\n\u5df2\u7ecf free<\/code><\/pre>\n\n\n\n
\u6b64\u65f6 p<\/code> \u8fd8\u4fdd\u5b58\u7740\u5730\u5740\uff0c\u4f46\u90a3\u5757\u5185\u5b58\u5df2\u7ecf\u4e0d\u80fd\u518d\u4f7f\u7528\u3002<\/p>\n\n\n\n
\u8fd9\u79cd\u60c5\u51b5\u901a\u5e38\u79f0\u4e3a\uff1a<\/p>\n\n\n\n
\u60ac\u7a7a\u6307\u9488\uff08dangling pointer\uff09<\/strong><\/p>\n\n\n\n
\u4e5f\u5e38\u88ab\u5f52\u5165\u5927\u5bb6\u5e38\u8bf4\u7684\u201c\u91ce\u6307\u9488\u201d\u95ee\u9898\u3002<\/p>\n\n\n\n
\n\n\n\n
\u5341\u4e5d\u3001free \u540e\u7f6e NULL<\/h1>\n\n\n\n
\u4e00\u4e2a\u5e38\u89c1\u7684\u5b89\u5168\u4e60\u60ef\uff1a<\/p>\n\n\n\n
<\/a>free(<\/span>p);<\/span><\/span>\n<\/a>p =<\/span> NULL;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8fd9\u6837\uff1a<\/p>\n\n\n\n
free\n \u2193\n\u91ca\u653e\u5185\u5b58\n\np = NULL\n \u2193\n\u4e0d\u518d\u6307\u5411\u65e7\u5730\u5740<\/code><\/pre>\n\n\n\n
\u4e4b\u540e\u53ef\u4ee5\u68c0\u67e5\uff1a<\/p>\n\n\n\n
<\/a>if<\/span> (<\/span>p ==<\/span> NULL)<\/span> {<\/span><\/span>\n<\/a>    printf(<\/span>\"p \u6ca1\u6709\u6307\u5411\u6709\u6548\u5185\u5b58<\/span>\\n<\/span>\"<\/span>);<\/span><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\n\n\n\n
\u4e8c\u5341\u3001\u4e0d\u80fd\u91cd\u590d free<\/h1>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>));<\/span><\/span>\n<\/a><\/span>\n<\/a>free(<\/span>p);<\/span><\/span>\n<\/a>free(<\/span>p);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8fd9\u662f\u9519\u8bef\u7684\u3002<\/p>\n\n\n\n
\u540c\u4e00\u5757\u52a8\u6001\u5185\u5b58\u4e0d\u80fd\u968f\u610f\u91ca\u653e\u4e24\u6b21\u3002<\/p>\n\n\n\n
\u8fd9\u79cd\u95ee\u9898\u53eb\uff1a<\/p>\n\n\n\n
double free<\/strong><\/p>\n\n\n\n
\u66f4\u5b89\u5168\u7684\u5199\u6cd5\uff1a<\/p>\n\n\n\n
<\/a>free(<\/span>p);<\/span><\/span>\n<\/a>p =<\/span> NULL;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u7b2c\u4e8c\u6b21\u5982\u679c\uff1a<\/p>\n\n\n\n
<\/a>free(<\/span>p);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u56e0\u4e3a p<\/code> \u5df2\u7ecf\u662f\nNULL<\/code>\uff0c\u901a\u5e38\u4e0d\u4f1a\u518d\u6b21\u91ca\u653e\u521a\u624d\u90a3\u5757\u5185\u5b58\u3002<\/p>\n\n\n\n
\u4e0d\u8fc7\u66f4\u91cd\u8981\u7684\u662f\uff1a<\/p>\n\n\n\n
\u7ba1\u7406\u597d\u6bcf\u5757\u5185\u5b58\u7684\u6240\u6709\u6743\u548c\u751f\u547d\u5468\u671f\u3002<\/strong><\/p>\n\n\n\n
\n\n\n\n
\u4e8c\u5341\u4e00\u3001\u52a8\u6001\u5185\u5b58\u4e0e\u6570\u7ec4<\/h1>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>arr =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>)<\/span> *<\/span> 5<\/span>);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u53ef\u4ee5\u50cf\u6570\u7ec4\u4e00\u6837\uff1a<\/p>\n\n\n\n
<\/a>arr[<\/span>0<\/span>]<\/span> =<\/span> 10<\/span>;<\/span><\/span>\n<\/a>arr[<\/span>1<\/span>]<\/span> =<\/span> 20<\/span>;<\/span><\/span>\n<\/a>arr[<\/span>2<\/span>]<\/span> =<\/span> 30<\/span>;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4e5f\u53ef\u4ee5\u4f7f\u7528\u6307\u9488\uff1a<\/p>\n\n\n\n
<\/a>*(<\/span>arr +<\/span> 0<\/span>)<\/span> =<\/span> 10<\/span>;<\/span><\/span>\n<\/a>*(<\/span>arr +<\/span> 1<\/span>)<\/span> =<\/span> 20<\/span>;<\/span><\/span>\n<\/a>*(<\/span>arr +<\/span> 2<\/span>)<\/span> =<\/span> 30<\/span>;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8fd9\u548c\u4e4b\u524d\u5b66\u4e60\u7684\u6570\u7ec4\u3001\u6307\u9488\u5b8c\u5168\u8054\u7cfb\u8d77\u6765\u4e86\u3002<\/p>\n\n\n\n
\u56e0\u4e3a\uff1a<\/p>\n\n\n\n
<\/a>arr[<\/span>i]<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u672c\u8d28\u4e0a\u5c31\u662f\uff1a<\/p>\n\n\n\n
<\/a>*(<\/span>arr +<\/span> i)<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\n\n\n\n
\u4e8c\u5341\u4e8c\u3001malloc + for<\/h1>\n\n\n\n
\u4f8b\u5982\u52a8\u6001\u521b\u5efa\u4e00\u4e2a\u6570\u7ec4\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> n =<\/span> 5<\/span>;<\/span><\/span>\n<\/a><\/span>\n<\/a>int<\/span> *<\/span>arr =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>)<\/span> *<\/span> n);<\/span><\/span>\n<\/a><\/span>\n<\/a>if<\/span> (<\/span>arr ==<\/span> NULL)<\/span> {<\/span><\/span>\n<\/a>    return<\/span> 1<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span>\n<\/a><\/span>\n<\/a>for<\/span> (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i <<\/span> n;<\/span> i++)<\/span> {<\/span><\/span>\n<\/a>    arr[<\/span>i]<\/span> =<\/span> (<\/span>i +<\/span> 1<\/span>)<\/span> *<\/span> 10<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span>\n<\/a><\/span>\n<\/a>for<\/span> (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i <<\/span> n;<\/span> i++)<\/span> {<\/span><\/span>\n<\/a>    printf(<\/span>\"<\/span>%d<\/span> \"<\/span>,<\/span> arr[<\/span>i]);<\/span><\/span>\n<\/a>}<\/span><\/span>\n<\/a><\/span>\n<\/a>free(<\/span>arr);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8f93\u51fa\uff1a<\/p>\n\n\n\n
10 20 30 40 50<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u4e8c\u5341\u4e09\u3001calloc<\/h1>\n\n\n\n
\u9664\u4e86 malloc<\/code>\uff0c\u8fd8\u6709\uff1a<\/p>\n\n\n\n
<\/a>calloc<\/span><\/code><\/pre><\/div>\n\n\n\n
\u57fa\u672c\u683c\u5f0f\uff1a<\/p>\n\n\n\n
<\/a>calloc(<\/span>\u5143\u7d20\u6570\u91cf,<\/span> \u6bcf\u4e2a\u5143\u7d20\u5927\u5c0f);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>arr =<\/span> calloc(<\/span>5<\/span>,<\/span> sizeof<\/span>(<\/span>int<\/span>));<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8868\u793a\uff1a<\/p>\n\n\n\n
5 \u4e2a int<\/code><\/pre>\n\n\n\n
\u548c\uff1a<\/p>\n\n\n\n
<\/a>malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>)<\/span> *<\/span> 5<\/span>)<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u7c7b\u4f3c\u3002<\/p>\n\n\n\n
\u4e00\u4e2a\u91cd\u8981\u533a\u522b\u662f\uff1a<\/p>\n\n\n\n
calloc<\/code> \u5206\u914d\u7684\u5185\u5b58\u4f1a\u88ab\u521d\u59cb\u5316\u4e3a\u96f6\u3002<\/strong><\/p>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>arr =<\/span> calloc(<\/span>5<\/span>,<\/span> sizeof<\/span>(<\/span>int<\/span>));<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u901a\u5e38\u53ef\u4ee5\u76f4\u63a5\u5f97\u5230\uff1a<\/p>\n\n\n\n
0 0 0 0 0<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u4e8c\u5341\u56db\u3001malloc \u548c calloc<\/h1>\n\n\n\n
\u53ef\u4ee5\u7b80\u5355\u8bb0\uff1a<\/p>\n\n\n\n
malloc\n\u2193\n\u7533\u8bf7\u5185\u5b58\n\u2193\n\u5185\u5bb9\u672a\u521d\u59cb\u5316\n\ncalloc\n\u2193\n\u7533\u8bf7\u5185\u5b58\n\u2193\n\u521d\u59cb\u5316\u4e3a 0<\/code><\/pre>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>a =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>)<\/span> *<\/span> 5<\/span>);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u91cc\u9762\u539f\u672c\u662f\u4ec0\u4e48\u503c\uff0c\u4e0d\u5e94\u8be5\u4f9d\u8d56\u3002<\/p>\n\n\n\n
\u800c\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>b =<\/span> calloc(<\/span>5<\/span>,<\/span> sizeof<\/span>(<\/span>int<\/span>));<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5f97\u5230\u7684\u5143\u7d20\u4f1a\u521d\u59cb\u5316\u4e3a 0\u3002<\/p>\n\n\n\n
\n\n\n\n
\u4e8c\u5341\u4e94\u3001realloc<\/h1>\n\n\n\n
\u5982\u679c\u5df2\u7ecf\u7533\u8bf7\u4e86\u4e00\u5757\u52a8\u6001\u5185\u5b58\uff0c\u4f46\u662f\u540e\u6765\u53d1\u73b0\uff1a<\/p>\n\n\n\n
\u4e0d\u591f\u7528\u4e86<\/code><\/pre>\n\n\n\n
\u53ef\u4ee5\u4f7f\u7528\uff1a<\/p>\n\n\n\n
<\/a>realloc<\/span><\/code><\/pre><\/div>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>)<\/span> *<\/span> 5<\/span>);<\/span><\/span>\n<\/a><\/span>\n<\/a>p =<\/span> realloc(<\/span>p,<\/span> sizeof<\/span>(<\/span>int<\/span>)<\/span> *<\/span> 10<\/span>);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u539f\u672c\uff1a<\/p>\n\n\n\n
5 \u4e2a int<\/code><\/pre>\n\n\n\n
\u53d8\u6210\uff1a<\/p>\n\n\n\n
10 \u4e2a int<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u4e8c\u5341\u516d\u3001realloc \u7684\u4f5c\u7528<\/h1>\n\n\n\n
\u53ef\u4ee5\u7406\u89e3\u6210\uff1a<\/p>\n\n\n\n
malloc\n \u2193\n\u7533\u8bf7 5 \u4e2a\u5143\u7d20\n\n\u4f7f\u7528\n\n\u53d1\u73b0\u4e0d\u591f\n \u2193\nrealloc\n \u2193\n\u8c03\u6574\u7a7a\u95f4\u5927\u5c0f<\/code><\/pre>\n\n\n\n
\u5b83\u53ef\u4ee5\uff1a<\/p>\n\n\n\n
\u6269\u5927<\/code><\/pre>\n\n\n\n
\u4e5f\u53ef\u4ee5\uff1a<\/p>\n\n\n\n
\u7f29\u5c0f<\/code><\/pre>\n\n\n\n
\u52a8\u6001\u6570\u7ec4\u7ecf\u5e38\u4f1a\u4f7f\u7528\u5b83\u3002<\/p>\n\n\n\n
\n\n\n\n
\u4e8c\u5341\u4e03\u3001realloc\n\u7684\u4e00\u4e2a\u91cd\u8981\u95ee\u9898<\/h1>\n\n\n\n
\u4e0d\u8981\u76f4\u63a5\u4e60\u60ef\u6027\u5199\uff1a<\/p>\n\n\n\n
<\/a>p =<\/span> realloc(<\/span>p,<\/span> new_size);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u56e0\u4e3a\u5982\u679c realloc<\/code> \u5931\u8d25\uff1a<\/p>\n\n\n\n
realloc \u8fd4\u56de NULL<\/code><\/pre>\n\n\n\n
\u90a3\u4e48\u539f\u6765\u7684\u5730\u5740\u53ef\u80fd\u5c31\u4e22\u5931\u4e86\u3002<\/p>\n\n\n\n
\u66f4\u5b89\u5168\u7684\u5199\u6cd5\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>temp =<\/span> realloc(<\/span>p,<\/span> new_size);<\/span><\/span>\n<\/a><\/span>\n<\/a>if<\/span> (<\/span>temp ==<\/span> NULL)<\/span> {<\/span><\/span>\n<\/a>    printf(<\/span>\"realloc failed<\/span>\\n<\/span>\"<\/span>);<\/span><\/span>\n<\/a>}<\/span> else<\/span> {<\/span><\/span>\n<\/a>    p =<\/span> temp;<\/span><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4e5f\u5c31\u662f\uff1a<\/p>\n\n\n\n
\u65e7\u6307\u9488 p\n   \u2193\nrealloc\n   \u2193\n\u4e34\u65f6\u6307\u9488 temp\n   \u2193\n\u68c0\u67e5\u6210\u529f\n   \u2193\np = temp<\/code><\/pre>\n\n\n\n
\u8fd9\u662f\u4e00\u79cd\u5f88\u91cd\u8981\u7684\u52a8\u6001\u5185\u5b58\u7f16\u7a0b\u4e60\u60ef\u3002<\/p>\n\n\n\n
\n\n\n\n
\u4e8c\u5341\u516b\u3001realloc \u793a\u4f8b<\/h1>\n\n\n\n
<\/a>#include <\/span><stdio.h><\/span><\/span>\n<\/a>#include <\/span><stdlib.h><\/span><\/span>\n<\/a><\/span>\n<\/a>int<\/span> main()<\/span> {<\/span><\/span>\n<\/a><\/span>\n<\/a>    int<\/span> *<\/span>arr =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>)<\/span> *<\/span> 5<\/span>);<\/span><\/span>\n<\/a><\/span>\n<\/a>    if<\/span> (<\/span>arr ==<\/span> NULL)<\/span> {<\/span><\/span>\n<\/a>        return<\/span> 1<\/span>;<\/span><\/span>\n<\/a>    }<\/span><\/span>\n<\/a><\/span>\n<\/a>    for<\/span> (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i <<\/span> 5<\/span>;<\/span> i++)<\/span> {<\/span><\/span>\n<\/a>        arr[<\/span>i]<\/span> =<\/span> i +<\/span> 1<\/span>;<\/span><\/span>\n<\/a>    }<\/span><\/span>\n<\/a><\/span>\n<\/a>    int<\/span> *<\/span>temp =<\/span> realloc(<\/span>arr,<\/span> sizeof<\/span>(<\/span>int<\/span>)<\/span> *<\/span> 10<\/span>);<\/span><\/span>\n<\/a><\/span>\n<\/a>    if<\/span> (<\/span>temp ==<\/span> NULL)<\/span> {<\/span><\/span>\n<\/a>        free(<\/span>arr);<\/span><\/span>\n<\/a>        return<\/span> 1<\/span>;<\/span><\/span>\n<\/a>    }<\/span><\/span>\n<\/a><\/span>\n<\/a>    arr =<\/span> temp;<\/span><\/span>\n<\/a><\/span>\n<\/a>    for<\/span> (<\/span>int<\/span> i =<\/span> 5<\/span>;<\/span> i <<\/span> 10<\/span>;<\/span> i++)<\/span> {<\/span><\/span>\n<\/a>        arr[<\/span>i]<\/span> =<\/span> i +<\/span> 1<\/span>;<\/span><\/span>\n<\/a>    }<\/span><\/span>\n<\/a><\/span>\n<\/a>    for<\/span> (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i <<\/span> 10<\/span>;<\/span> i++)<\/span> {<\/span><\/span>\n<\/a>        printf(<\/span>\"<\/span>%d<\/span> \"<\/span>,<\/span> arr[<\/span>i]);<\/span><\/span>\n<\/a>    }<\/span><\/span>\n<\/a><\/span>\n<\/a>    free(<\/span>arr);<\/span><\/span>\n<\/a><\/span>\n<\/a>    return<\/span> 0<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8f93\u51fa\uff1a<\/p>\n\n\n\n
1 2 3 4 5 6 7 8 9 10<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u4e8c\u5341\u4e5d\u3001\u52a8\u6001\u5185\u5b58\u548c\u7ed3\u6784\u4f53<\/h1>\n\n\n\n
\u73b0\u5728\u628a\u4e0a\u4e00\u7ae0\u7684\u7ed3\u6784\u4f53\u63a5\u8fdb\u6765\u3002<\/p>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>struct<\/span> Student {<\/span><\/span>\n<\/a>    char<\/span> name[<\/span>50<\/span>];<\/span><\/span>\n<\/a>    int<\/span> age;<\/span><\/span>\n<\/a>    double<\/span> score;<\/span><\/span>\n<\/a>};<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u53ef\u4ee5\u52a8\u6001\u7533\u8bf7\u4e00\u4e2a\uff1a<\/p>\n\n\n\n
<\/a>struct<\/span> Student *<\/span>p;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u7136\u540e\uff1a<\/p>\n\n\n\n
<\/a>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>struct<\/span> Student));<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8fd9\u6837\u5c31\u5728\u5806\u4e0a\u7533\u8bf7\u4e86\u4e00\u4e2a Student<\/code> \u5927\u5c0f\u7684\u7a7a\u95f4\u3002<\/p>\n\n\n\n
\n\n\n\n
\u4e09\u5341\u3001\u7ed3\u6784\u4f53 + malloc<\/h1>\n\n\n\n
\u5b8c\u6574\u4f8b\u5b50\uff1a<\/p>\n\n\n\n
<\/a>#include <\/span><stdio.h><\/span><\/span>\n<\/a>#include <\/span><stdlib.h><\/span><\/span>\n<\/a><\/span>\n<\/a>struct<\/span> Student {<\/span><\/span>\n<\/a>    char<\/span> name[<\/span>50<\/span>];<\/span><\/span>\n<\/a>    int<\/span> age;<\/span><\/span>\n<\/a>    double<\/span> score;<\/span><\/span>\n<\/a>};<\/span><\/span>\n<\/a><\/span>\n<\/a>int<\/span> main()<\/span> {<\/span><\/span>\n<\/a><\/span>\n<\/a>    struct<\/span> Student *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>struct<\/span> Student));<\/span><\/span>\n<\/a><\/span>\n<\/a>    if<\/span> (<\/span>p ==<\/span> NULL)<\/span> {<\/span><\/span>\n<\/a>        return<\/span> 1<\/span>;<\/span><\/span>\n<\/a>    }<\/span><\/span>\n<\/a><\/span>\n<\/a>    p-><\/span>age =<\/span> 18<\/span>;<\/span><\/span>\n<\/a>    p-><\/span>score =<\/span> 95.5<\/span>;<\/span><\/span>\n<\/a><\/span>\n<\/a>    printf(<\/span>\"age = <\/span>%d\\n<\/span>\"<\/span>,<\/span> p-><\/span>age);<\/span><\/span>\n<\/a>    printf(<\/span>\"score = <\/span>%.2f\\n<\/span>\"<\/span>,<\/span> p-><\/span>score);<\/span><\/span>\n<\/a><\/span>\n<\/a>    free(<\/span>p);<\/span><\/span>\n<\/a>    p =<\/span> NULL;<\/span><\/span>\n<\/a><\/span>\n<\/a>    return<\/span> 0<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8fd9\u91cc\u540c\u65f6\u4f7f\u7528\u4e86\uff1a<\/p>\n\n\n\n
\u7ed3\u6784\u4f53\n+\n\u7ed3\u6784\u4f53\u6307\u9488\n+\nmalloc\n+\nfree\n+\n-><\/code><\/pre>\n\n\n\n
\n\n\n\n
\u4e09\u5341\u4e00\u3001\u52a8\u6001\u521b\u5efa\u7ed3\u6784\u4f53\u6570\u7ec4<\/h1>\n\n\n\n
\u8fd8\u53ef\u4ee5\u4e00\u6b21\u7533\u8bf7\u591a\u4e2a\u7ed3\u6784\u4f53\uff1a<\/p>\n\n\n\n
<\/a>struct<\/span> Student *<\/span>students =<\/span><\/span>\n<\/a>    malloc(<\/span>sizeof<\/span>(<\/span>struct<\/span> Student)<\/span> *<\/span> 100<\/span>);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8868\u793a\uff1a<\/p>\n\n\n\n
100 \u4e2a Student<\/code><\/pre>\n\n\n\n
\u7136\u540e\uff1a<\/p>\n\n\n\n
<\/a>students[<\/span>0<\/span>].<\/span>age =<\/span> 18<\/span>;<\/span><\/span>\n<\/a>students[<\/span>1<\/span>].<\/span>age =<\/span> 19<\/span>;<\/span><\/span>\n<\/a>students[<\/span>2<\/span>].<\/span>age =<\/span> 20<\/span>;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u6216\u8005\uff1a<\/p>\n\n\n\n
<\/a>(<\/span>students +<\/span> 0<\/span>)-><\/span>age =<\/span> 18<\/span>;<\/span><\/span>\n<\/a>(<\/span>students +<\/span> 1<\/span>)-><\/span>age =<\/span> 19<\/span>;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8fd9\u91cc\u53c8\u548c\u4e4b\u524d\u7684\uff1a<\/p>\n\n\n\n
\u6570\u7ec4\n\u6307\u9488\n\u7ed3\u6784\u4f53<\/code><\/pre>\n\n\n\n
\u5168\u90e8\u8fde\u63a5\u8d77\u6765\u4e86\u3002<\/p>\n\n\n\n
\n\n\n\n
\u4e09\u5341\u4e8c\u3001typedef + malloc<\/h1>\n\n\n\n
\u5982\u679c\u4e4b\u524d\u4f7f\u7528\u4e86\uff1a<\/p>\n\n\n\n
<\/a>typedef<\/span> struct<\/span> {<\/span><\/span>\n<\/a>    char<\/span> name[<\/span>50<\/span>];<\/span><\/span>\n<\/a>    int<\/span> age;<\/span><\/span>\n<\/a>    double<\/span> score;<\/span><\/span>\n<\/a>}<\/span> Student;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u90a3\u4e48\u53ef\u4ee5\u5199\uff1a<\/p>\n\n\n\n
<\/a>Student *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>Student));<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u800c\u4e0d\u662f\uff1a<\/p>\n\n\n\n
<\/a>struct<\/span> Student *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>struct<\/span> Student));<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>Student *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>Student));<\/span><\/span>\n<\/a><\/span>\n<\/a>if<\/span> (<\/span>p ==<\/span> NULL)<\/span> {<\/span><\/span>\n<\/a>    return<\/span> 1<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span>\n<\/a><\/span>\n<\/a>p-><\/span>age =<\/span> 18<\/span>;<\/span><\/span>\n<\/a><\/span>\n<\/a>free(<\/span>p);<\/span><\/span>\n<\/a>p =<\/span> NULL;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\n\n\n\n
\u4e09\u5341\u4e09\u3001\u52a8\u6001\u5b57\u7b26\u4e32<\/h1>\n\n\n\n
\u52a8\u6001\u5185\u5b58\u4e0d\u53ea\u53ef\u4ee5\u4fdd\u5b58\u6570\u5b57\u3002<\/p>\n\n\n\n
\u4f8b\u5982\u5b57\u7b26\u4e32\uff1a<\/p>\n\n\n\n
<\/a>char<\/span> *<\/span>str =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>char<\/span>)<\/span> *<\/span> 100<\/span>);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u7136\u540e\uff1a<\/p>\n\n\n\n
<\/a>scanf(<\/span>\"<\/span>%99s<\/span>\"<\/span>,<\/span> str);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4f7f\u7528\u7ed3\u675f\uff1a<\/p>\n\n\n\n
<\/a>free(<\/span>str);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4e5f\u53ef\u4ee5\u5199\uff1a<\/p>\n\n\n\n
<\/a>char<\/span> *<\/span>str =<\/span> malloc(<\/span>100<\/span>);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u56e0\u4e3a char<\/code> \u901a\u5e38\u5360 1 \u5b57\u8282\u3002<\/p>\n\n\n\n
\u4f46\u66f4\u52a0\u63a8\u8350\u660e\u786e\u8868\u8fbe\u610f\u56fe\uff1a<\/p>\n\n\n\n
<\/a>char<\/span> *<\/span>str =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>char<\/span>)<\/span> *<\/span> 100<\/span>);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\n\n\n\n
\u4e09\u5341\u56db\u3001\u52a8\u6001\u4e8c\u7ef4\u6570\u7ec4<\/h1>\n\n\n\n
\u7b80\u5355\u60c5\u51b5\u4e0b\uff0c\u4e5f\u53ef\u4ee5\u7533\u8bf7\u4e00\u6574\u5757\u8fde\u7eed\u5185\u5b58\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> rows =<\/span> 3<\/span>;<\/span><\/span>\n<\/a>int<\/span> cols =<\/span> 4<\/span>;<\/span><\/span>\n<\/a><\/span>\n<\/a>int<\/span> *<\/span>arr =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>)<\/span> *<\/span> rows *<\/span> cols);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8bbf\u95ee\uff1a<\/p>\n\n\n\n
<\/a>arr[<\/span>i *<\/span> cols +<\/span> j]<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>arr[<\/span>0<\/span> *<\/span> cols +<\/span> 0<\/span>]<\/span><\/span>\n<\/a>arr[<\/span>0<\/span> *<\/span> cols +<\/span> 1<\/span>]<\/span><\/span>\n<\/a>arr[<\/span>1<\/span> *<\/span> cols +<\/span> 0<\/span>]<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u53ef\u4ee5\u628a\u4e8c\u7ef4\u6570\u636e\u653e\u5728\u4e00\u7ef4\u7684\u8fde\u7eed\u5185\u5b58\u91cc\u3002<\/p>\n\n\n\n
\u540e\u9762\u5b66\u4e60\u66f4\u590d\u6742\u7684\u6570\u636e\u7ed3\u6784\u65f6\uff0c\u8fd9\u79cd\u601d\u60f3\u4f1a\u975e\u5e38\u5e38\u89c1\u3002<\/p>\n\n\n\n
\n\n\n\n
\u4e09\u5341\u4e94\u3001sizeof \u4e0e\u52a8\u6001\u5185\u5b58<\/h1>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>)<\/span> *<\/span> 10<\/span>);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u6ce8\u610f\uff1a<\/p>\n\n\n\n
<\/a>sizeof<\/span>(<\/span>p)<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u548c\uff1a<\/p>\n\n\n\n
<\/a>sizeof<\/span>(*<\/span>p)<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4e0d\u662f\u4e00\u56de\u4e8b\u3002<\/p>\n\n\n\n
p<\/code> \u662f\u6307\u9488\uff1a<\/p>\n\n\n\n
<\/a>sizeof<\/span>(<\/span>p)<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5f97\u5230\u7684\u662f\uff1a<\/p>\n\n\n\n
\u6307\u9488\u672c\u8eab\u7684\u5927\u5c0f\u3002<\/strong><\/p>\n\n\n\n
\u800c\uff1a<\/p>\n\n\n\n
<\/a>sizeof<\/span>(*<\/span>p)<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5f97\u5230\u7684\u662f\uff1a<\/p>\n\n\n\n
p \u6307\u5411\u7684\u6570\u636e\u7c7b\u578b\u5927\u5c0f\u3002<\/strong><\/p>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u90a3\u4e48\uff1a<\/p>\n\n\n\n
<\/a>sizeof<\/span>(<\/span>p)<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u662f\u6307\u9488\u5927\u5c0f\u3002<\/p>\n\n\n\n
\u800c\uff1a<\/p>\n\n\n\n
<\/a>sizeof<\/span>(*<\/span>p)<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u662f int<\/code> \u7684\u5927\u5c0f\u3002<\/p>\n\n\n\n
\u56e0\u6b64\u52a8\u6001\u6570\u7ec4\u7533\u8bf7\u65f6\uff1a<\/p>\n\n\n\n
<\/a>malloc(<\/span>sizeof<\/span>(*<\/span>p)<\/span> *<\/span> n);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4e5f\u662f\u4e00\u79cd\u5f88\u5b9e\u7528\u7684\u5199\u6cd5\u3002<\/p>\n\n\n\n
\n\n\n\n
\u4e09\u5341\u516d\u3001\u52a8\u6001\u5185\u5b58\u548c\u666e\u901a\u6570\u7ec4\u7684\u533a\u522b<\/h1>\n\n\n\n
\u666e\u901a\u6570\u7ec4\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> arr[<\/span>10<\/span>];<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u7279\u70b9\uff1a<\/p>\n\n\n\n
\u5927\u5c0f\u901a\u5e38\u5728\u5b9a\u4e49\u65f6\u786e\u5b9a\n\u751f\u547d\u5468\u671f\u7531\u4f5c\u7528\u57df\u7b49\u89c4\u5219\u7ba1\u7406\n\u4e0d\u9700\u8981\u624b\u52a8 free<\/code><\/pre>\n\n\n\n
\u52a8\u6001\u6570\u7ec4\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>arr =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>)<\/span> *<\/span> n);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u7279\u70b9\uff1a<\/p>\n\n\n\n
\u5927\u5c0f\u53ef\u4ee5\u8fd0\u884c\u65f6\u51b3\u5b9a\n\u751f\u547d\u5468\u671f\u7531\u7a0b\u5e8f\u5458\u7ba1\u7406\n\u9700\u8981 free<\/code><\/pre>\n\n\n\n
\u53ef\u4ee5\u7b80\u5355\u7406\u89e3\uff1a<\/p>\n\n\n\n
\u666e\u901a\u6570\u7ec4\n\u2193\n\u7f16\u8bd1\/\u5b9a\u4e49\u65f6\u51b3\u5b9a\u5927\u5c0f\n\n\u52a8\u6001\u5185\u5b58\n\u2193\n\u8fd0\u884c\u65f6\u51b3\u5b9a\u5927\u5c0f<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u4e09\u5341\u4e03\u3001\u5e38\u89c1\u9519\u8bef<\/h1>\n\n\n\n
1. \u6ca1\u6709\u68c0\u67e5 malloc<\/h2>\n\n\n\n
\u4e0d\u63a8\u8350\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>));<\/span><\/span>\n<\/a><\/span>\n<\/a>*<\/span>p =<\/span> 10<\/span>;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u66f4\u5b89\u5168\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>));<\/span><\/span>\n<\/a><\/span>\n<\/a>if<\/span> (<\/span>p ==<\/span> NULL)<\/span> {<\/span><\/span>\n<\/a>    return<\/span> 1<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span>\n<\/a><\/span>\n<\/a>*<\/span>p =<\/span> 10<\/span>;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\n\n\n\n
2. \u4f7f\u7528\u672a\u521d\u59cb\u5316\u7684 malloc \u5185\u5b58<\/h2>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>));<\/span><\/span>\n<\/a><\/span>\n<\/a>printf(<\/span>\"<\/span>%d\\n<\/span>\"<\/span>,<\/span> *<\/span>p);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4e0d\u80fd\u4f9d\u8d56\u8fd9\u91cc\u662f\u4ec0\u4e48\u503c\u3002<\/p>\n\n\n\n
\u5e94\u8be5\u5148\u5199\u5165\uff1a<\/p>\n\n\n\n
<\/a>*<\/span>p =<\/span> 10<\/span>;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u518d\u8bfb\u53d6\u3002<\/p>\n\n\n\n
\n\n\n\n
3. \u5fd8\u8bb0 free<\/h2>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>));<\/span><\/span>\n<\/a>*<\/span>p =<\/span> 10<\/span>;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5982\u679c\u4e0d\u518d\u4f7f\u7528\uff0c\u5374\u6ca1\u6709\uff1a<\/p>\n\n\n\n
<\/a>free(<\/span>p);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5c31\u53ef\u80fd\u5bfc\u81f4\u5185\u5b58\u6cc4\u6f0f\u3002<\/p>\n\n\n\n
\n\n\n\n
4. free \u540e\u7ee7\u7eed\u4f7f\u7528<\/h2>\n\n\n\n
\u9519\u8bef\uff1a<\/p>\n\n\n\n
<\/a>free(<\/span>p);<\/span><\/span>\n<\/a><\/span>\n<\/a>printf(<\/span>\"<\/span>%d\\n<\/span>\"<\/span>,<\/span> *<\/span>p);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u91ca\u653e\u540e\u4e0d\u8981\u7ee7\u7eed\u8bbf\u95ee\u3002<\/p>\n\n\n\n
\n\n\n\n
5. \u91cd\u590d free<\/h2>\n\n\n\n
\u9519\u8bef\uff1a<\/p>\n\n\n\n
<\/a>free(<\/span>p);<\/span><\/span>\n<\/a>free(<\/span>p);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4e0d\u8981\u91cd\u590d\u91ca\u653e\u540c\u4e00\u5757\u5185\u5b58\u3002<\/p>\n\n\n\n
\n\n\n\n
6. \u8d8a\u754c<\/h2>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>)<\/span> *<\/span> 5<\/span>);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5408\u6cd5\uff1a<\/p>\n\n\n\n
<\/a>p[<\/span>0<\/span>]<\/span><\/span>\n<\/a>p[<\/span>1<\/span>]<\/span><\/span>\n<\/a>p[<\/span>2<\/span>]<\/span><\/span>\n<\/a>p[<\/span>3<\/span>]<\/span><\/span>\n<\/a>p[<\/span>4<\/span>]<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u9519\u8bef\uff1a<\/p>\n\n\n\n
<\/a>p[<\/span>5<\/span>]<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u56e0\u4e3a\u4f60\u53ea\u7533\u8bf7\u4e86 5 \u4e2a\u5143\u7d20\u3002<\/p>\n\n\n\n
\n\n\n\n
\u4e09\u5341\u516b\u3001\u52a8\u6001\u5185\u5b58\u7684\u751f\u547d\u5468\u671f<\/h1>\n\n\n\n
\u53ef\u4ee5\u628a\u52a8\u6001\u5185\u5b58\u7406\u89e3\u6210\uff1a<\/p>\n\n\n\n
\u7533\u8bf7\n \u2193\nmalloc \/ calloc\n \u2193\n\u68c0\u67e5\n \u2193\n\u4f7f\u7528\n \u2193\nrealloc\uff08\u9700\u8981\u8c03\u6574\u65f6\uff09\n \u2193\n\u7ee7\u7eed\u4f7f\u7528\n \u2193\nfree\n \u2193\n\u7ed3\u675f<\/code><\/pre>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>)<\/span> *<\/span> 10<\/span>);<\/span><\/span>\n<\/a><\/span>\n<\/a>if<\/span> (<\/span>p ==<\/span> NULL)<\/span> {<\/span><\/span>\n<\/a>    return<\/span> 1<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span>\n<\/a><\/span>\n<\/a>\/* \u4f7f\u7528 p *\/<\/span><\/span>\n<\/a><\/span>\n<\/a>int<\/span> *<\/span>temp =<\/span> realloc(<\/span>p,<\/span> sizeof<\/span>(<\/span>int<\/span>)<\/span> *<\/span> 20<\/span>);<\/span><\/span>\n<\/a><\/span>\n<\/a>if<\/span> (<\/span>temp !=<\/span> NULL)<\/span> {<\/span><\/span>\n<\/a>    p =<\/span> temp;<\/span><\/span>\n<\/a>}<\/span><\/span>\n<\/a><\/span>\n<\/a>\/* \u7ee7\u7eed\u4f7f\u7528 p *\/<\/span><\/span>\n<\/a><\/span>\n<\/a>free(<\/span>p);<\/span><\/span>\n<\/a>p =<\/span> NULL;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\n\n\n\n
\u4e09\u5341\u4e5d\u3001\u4e00\u4e2a\u5b8c\u6574\u7684\u5c0f\u7a0b\u5e8f<\/h1>\n\n\n\n
\u5b9e\u73b0\uff1a<\/p>\n\n\n\n
\u7528\u6237\u8f93\u5165\u4eba\u6570\n\u2193\n\u52a8\u6001\u521b\u5efa\u5b66\u751f\u6570\u7ec4\n\u2193\n\u8f93\u5165\u5b66\u751f\u4fe1\u606f\n\u2193\n\u8f93\u51fa\u5b66\u751f\u4fe1\u606f\n\u2193\n\u91ca\u653e\u5185\u5b58<\/code><\/pre>\n\n\n\n
\u4ee3\u7801\uff1a<\/p>\n\n\n\n
<\/a>#include <\/span><stdio.h><\/span><\/span>\n<\/a>#include <\/span><stdlib.h><\/span><\/span>\n<\/a><\/span>\n<\/a>typedef<\/span> struct<\/span> {<\/span><\/span>\n<\/a>    char<\/span> name[<\/span>50<\/span>];<\/span><\/span>\n<\/a>    int<\/span> age;<\/span><\/span>\n<\/a>    double<\/span> score;<\/span><\/span>\n<\/a>}<\/span> Student;<\/span><\/span>\n<\/a><\/span>\n<\/a>int<\/span> main()<\/span> {<\/span><\/span>\n<\/a><\/span>\n<\/a>    int<\/span> n;<\/span><\/span>\n<\/a><\/span>\n<\/a>    printf(<\/span>\"\u8bf7\u8f93\u5165\u5b66\u751f\u6570\u91cf: \"<\/span>);<\/span><\/span>\n<\/a>    scanf(<\/span>\"<\/span>%d<\/span>\"<\/span>,<\/span> &<\/span>n);<\/span><\/span>\n<\/a><\/span>\n<\/a>    Student *<\/span>students =<\/span><\/span>\n<\/a>        malloc(<\/span>sizeof<\/span>(<\/span>Student)<\/span> *<\/span> n);<\/span><\/span>\n<\/a><\/span>\n<\/a>    if<\/span> (<\/span>students ==<\/span> NULL)<\/span> {<\/span><\/span>\n<\/a>        printf(<\/span>\"\u5185\u5b58\u7533\u8bf7\u5931\u8d25<\/span>\\n<\/span>\"<\/span>);<\/span><\/span>\n<\/a>        return<\/span> 1<\/span>;<\/span><\/span>\n<\/a>    }<\/span><\/span>\n<\/a><\/span>\n<\/a>    for<\/span> (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i <<\/span> n;<\/span> i++)<\/span> {<\/span><\/span>\n<\/a>        printf(<\/span>\"\u8bf7\u8f93\u5165\u7b2c <\/span>%d<\/span> \u4e2a\u5b66\u751f\u7684\u4fe1\u606f:<\/span>\\n<\/span>\"<\/span>,<\/span> i +<\/span> 1<\/span>);<\/span><\/span>\n<\/a><\/span>\n<\/a>        printf(<\/span>\"\u59d3\u540d: \"<\/span>);<\/span><\/span>\n<\/a>        scanf(<\/span>\"<\/span>%49s<\/span>\"<\/span>,<\/span> students[<\/span>i].<\/span>name);<\/span><\/span>\n<\/a><\/span>\n<\/a>        printf(<\/span>\"\u5e74\u9f84: \"<\/span>);<\/span><\/span>\n<\/a>        scanf(<\/span>\"<\/span>%d<\/span>\"<\/span>,<\/span> &<\/span>students[<\/span>i].<\/span>age);<\/span><\/span>\n<\/a><\/span>\n<\/a>        printf(<\/span>\"\u6210\u7ee9: \"<\/span>);<\/span><\/span>\n<\/a>        scanf(<\/span>\"<\/span>%lf<\/span>\"<\/span>,<\/span> &<\/span>students[<\/span>i].<\/span>score);<\/span><\/span>\n<\/a>    }<\/span><\/span>\n<\/a><\/span>\n<\/a>    printf(<\/span>\"<\/span>\\n<\/span>\u5b66\u751f\u4fe1\u606f:<\/span>\\n<\/span>\"<\/span>);<\/span><\/span>\n<\/a><\/span>\n<\/a>    for<\/span> (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i <<\/span> n;<\/span> i++)<\/span> {<\/span><\/span>\n<\/a>        printf(<\/span><\/span>\n<\/a>            \"<\/span>%s<\/span> <\/span>%d<\/span> <\/span>%.2f\\n<\/span>\"<\/span>,<\/span><\/span>\n<\/a>            students[<\/span>i].<\/span>name,<\/span><\/span>\n<\/a>            students[<\/span>i].<\/span>age,<\/span><\/span>\n<\/a>            students[<\/span>i].<\/span>score<\/span>\n<\/a>        );<\/span><\/span>\n<\/a>    }<\/span><\/span>\n<\/a><\/span>\n<\/a>    free(<\/span>students);<\/span><\/span>\n<\/a>    students =<\/span> NULL;<\/span><\/span>\n<\/a><\/span>\n<\/a>    return<\/span> 0<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8fd9\u4e2a\u4f8b\u5b50\u5df2\u7ecf\u628a\uff1a<\/p>\n\n\n\n
\u6570\u7ec4\n\u6307\u9488\n\u7ed3\u6784\u4f53\n\u51fd\u6570\n\u52a8\u6001\u5185\u5b58<\/code><\/pre>\n\n\n\n
\u5f00\u59cb\u771f\u6b63\u7ec4\u5408\u8d77\u6765\u4e86\u3002<\/p>\n\n\n\n
\n\n\n\n
\u56db\u5341\u3001\u672c\u7ae0\u6838\u5fc3\u77e5\u8bc6<\/h1>\n\n\n\n
\u8fd9\u4e00\u7ae0\u6700\u9700\u8981\u638c\u63e1\u7684\u4e0d\u662f\u6240\u6709\u51fd\u6570\uff0c\u800c\u662f\u4e0b\u9762\u8fd9\u6761\u601d\u8def\uff1a<\/p>\n\n\n\n
\u6307\u9488\u4fdd\u5b58\u5730\u5740\n        \u2193\nmalloc \u5728\u8fd0\u884c\u65f6\u7533\u8bf7\u5185\u5b58\n        \u2193\n\u6307\u9488\u6307\u5411\u8fd9\u5757\u5185\u5b58\n        \u2193\n\u901a\u8fc7\u6307\u9488\u4f7f\u7528\u5185\u5b58\n        \u2193\n\u4e0d\u9700\u8981\u4e86\n        \u2193\nfree \u91ca\u653e\u5185\u5b58<\/code><\/pre>\n\n\n\n
\u6700\u6838\u5fc3\u7684\u4ee3\u7801\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>));<\/span><\/span>\n<\/a><\/span>\n<\/a>if<\/span> (<\/span>p ==<\/span> NULL)<\/span> {<\/span><\/span>\n<\/a>    return<\/span> 1<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span>\n<\/a><\/span>\n<\/a>*<\/span>p =<\/span> 100<\/span>;<\/span><\/span>\n<\/a><\/span>\n<\/a>printf(<\/span>\"<\/span>%d\\n<\/span>\"<\/span>,<\/span> *<\/span>p);<\/span><\/span>\n<\/a><\/span>\n<\/a>free(<\/span>p);<\/span><\/span>\n<\/a>p =<\/span> NULL;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4ee5\u53ca\u52a8\u6001\u6570\u7ec4\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>arr =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>)<\/span> *<\/span> n);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\n\n\n\n
\u56db\u5341\u4e00\u3001\u7ec3\u4e60<\/h1>\n\n\n\n
\u7ec3\u4e60 1<\/h3>\n\n\n\n
\u4f7f\u7528 malloc<\/code> \u52a8\u6001\u7533\u8bf7\u4e00\u4e2a int<\/code>\uff1a<\/p>\n\n\n\n
\u8f93\u5165\u4e00\u4e2a\u6570\u5b57\n\u2193\n\u4fdd\u5b58\u5230\u52a8\u6001\u5185\u5b58\n\u2193\n\u8f93\u51fa\n\u2193\nfree<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u7ec3\u4e60 2<\/h3>\n\n\n\n
\u8ba9\u7528\u6237\u8f93\u5165 n<\/code>\uff1a<\/p>\n\n\n\n
n = ?<\/code><\/pre>\n\n\n\n
\u7136\u540e\u52a8\u6001\u7533\u8bf7\uff1a<\/p>\n\n\n\n
n \u4e2a int<\/code><\/pre>\n\n\n\n
\u4f7f\u7528 for<\/code> \u8f93\u5165\u6240\u6709\u6570\u5b57\uff0c\u518d\u5168\u90e8\u8f93\u51fa\u3002<\/p>\n\n\n\n
\n\n\n\n
\u7ec3\u4e60 3<\/h3>\n\n\n\n
\u4f7f\u7528\uff1a<\/p>\n\n\n\n
<\/a>calloc<\/span><\/code><\/pre><\/div>\n\n\n\n
\u52a8\u6001\u521b\u5efa 10 \u4e2a int<\/code>\uff0c\u89c2\u5bdf\u5b83\u4eec\u521d\u59cb\u503c\u3002<\/p>\n\n\n\n
\n\n\n\n
\u7ec3\u4e60 4<\/h3>\n\n\n\n
\u4f7f\u7528\uff1a<\/p>\n\n\n\n
<\/a>realloc<\/span><\/code><\/pre><\/div>\n\n\n\n
\u5148\u521b\u5efa 5 \u4e2a\u6574\u6570\uff0c\u518d\u6269\u5c55\u6210 10 \u4e2a\u6574\u6570\u3002<\/p>\n\n\n\n
\n\n\n\n
\u7ec3\u4e60 5<\/h3>\n\n\n\n
\u5199\u4e00\u4e2a\uff1a<\/p>\n\n\n\n
<\/a>void<\/span> double_array(<\/span>int<\/span> *<\/span>p,<\/span> int<\/span> n)<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u52a8\u6001\u7533\u8bf7\u6570\u7ec4\u540e\uff1a<\/p>\n\n\n\n
1 2 3 4 5<\/code><\/pre>\n\n\n\n
\u8c03\u7528\u51fd\u6570\u53d8\u6210\uff1a<\/p>\n\n\n\n
2 4 6 8 10<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u7ec3\u4e60 6<\/h3>\n\n\n\n
\u4f7f\u7528\uff1a<\/p>\n\n\n\n
<\/a>typedef<\/span> struct<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5b9a\u4e49 Student<\/code>\u3002<\/p>\n\n\n\n
\u7136\u540e\u52a8\u6001\u7533\u8bf7\u4e00\u4e2a\u5b66\u751f\uff1a<\/p>\n\n\n\n
<\/a>Student *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>Student));<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u901a\u8fc7\uff1a<\/p>\n\n\n\n
<\/a>p-><\/span>age<\/span><\/code><\/pre><\/div>\n\n\n\n
\u4fee\u6539\u5e74\u9f84\u3002<\/p>\n\n\n\n
\u6700\u540e\uff1a<\/p>\n\n\n\n
<\/a>free(<\/span>p);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\n\n\n\n
\u7ec3\u4e60 7<\/h3>\n\n\n\n
\u52a8\u6001\u521b\u5efa n<\/code> \u4e2a\u5b66\u751f\uff1a<\/p>\n\n\n\n
<\/a>Student *<\/span>students =<\/span><\/span>\n<\/a>    malloc(<\/span>sizeof<\/span>(<\/span>Student)<\/span> *<\/span> n);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8f93\u5165\u5e76\u8f93\u51fa\u5168\u90e8\u5b66\u751f\u4fe1\u606f\u3002<\/p>\n\n\n\n
\u8fd9\u662f\u672c\u7ae0\u6700\u91cd\u8981\u7684\u7efc\u5408\u7ec3\u4e60\u4e4b\u4e00\u3002<\/p>\n\n\n\n
\n\n\n\n
<\/h1>\n\n\n\n
<\/p>\n","protected":false},"excerpt":{"rendered":"
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