{"id":18,"date":"2016-04-02T15:15:59","date_gmt":"2016-04-02T07:15:59","guid":{"rendered":"http:\/\/www.91tfboys.com\/?p=18"},"modified":"2017-01-03T21:31:37","modified_gmt":"2017-01-03T13:31:37","slug":"%e5%9c%a864%e4%bd%8d%e7%bc%96%e8%af%91%e5%99%a8%e4%b8%8b%e7%94%a8sizeofstruct-a%e8%ae%a1%e7%ae%97%e5%87%ba%e7%9a%84%e5%a4%a7%e5%b0%8f%e6%98%af%e5%a4%9a%e5%b0%91","status":"publish","type":"post","link":"https:\/\/www.91tfboys.com\/?p=18","title":{"rendered":"\u572864\u4f4d\u7f16\u8bd1\u5668\u4e0b\u7528sizeof(struct A)\u8ba1\u7b97\u51fa\u7684\u5927\u5c0f\u662f\u591a\u5c11"},"content":{"rendered":"

\uff08\u539f\u6587\u94fe\u63a5http:\/\/www.nowcoder.com\/questionTerminal\/1f3927bd941146b8a9171255ca4626d0?orderByHotValue=0&done=0&pos=67&mutiTagIds=569&onlyReference=false<\/a>\uff09<\/p>\n

\u6709\u4e00\u4e2a\u5982\u4e0b\u7684\u7ed3\u6784\u4f53\uff1a<\/div>\n

<\/p>\n

\n
\n\n\n\n
\n
1<\/div>\n
2<\/div>\n
3<\/div>\n
4<\/div>\n
5<\/div>\n
6<\/div>\n<\/td>\n
\n
\n
struct<\/code> A{<\/code><\/div>\n
<\/code>long<\/code> a1;<\/code><\/div>\n
<\/code>short<\/code> a2;<\/code><\/div>\n
<\/code>int<\/code> a3;<\/code><\/div>\n
<\/code>int<\/code> *a4;<\/code><\/div>\n
};<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n
\u8bf7\u95ee\u572864\u4f4d\u7f16\u8bd1\u5668\u4e0b\u7528sizeof(struct A)\u8ba1\u7b97\u51fa\u7684\u5927\u5c0f\u662f\u591a\u5c11\uff1f<\/div>\n
    \n
  • 24<\/li>\n
  • 28<\/li>\n
  • 16<\/li>\n
  • 18<\/li>\n<\/ul>\n\n\n\n
    \n
    1<\/div>\n
    2<\/div>\n
    3<\/div>\n
    4<\/div>\n
    5<\/div>\n
    6<\/div>\n
    7<\/div>\n
    8<\/div>\n
    9<\/div>\n
    10<\/div>\n
    11<\/div>\n
    12<\/div>\n
    13<\/div>\n
    14<\/div>\n
    15<\/div>\n
    16<\/div>\n
    17<\/div>\n
    18<\/div>\n
    19<\/div>\n
    20<\/div>\n
    21<\/div>\n
    22<\/div>\n
    23<\/div>\n<\/td>\n
    		\n
    \n
    8 + 2 + 4 + 8 = 22\uff0c \u5bf9\u9f50\u4e3a24<\/code><\/div>\n
    32\u4f4d\u7f16\u8bd1\u5668\uff1a32\u4f4d\u7cfb\u7edf\u4e0b\u6307\u9488\u5360\u75284\u5b57\u8282<\/code><\/div>\n
    <\/code>char<\/code> \uff1a1\u4e2a\u5b57\u8282<\/code><\/div>\n
    <\/code>char<\/code>*\uff08\u5373\u6307\u9488\u53d8\u91cf\uff09: 4\u4e2a\u5b57\u8282\uff0832\u4f4d\u7684\u5bfb\u5740\u7a7a\u95f4\u662f2^32, \u537332\u4e2abit\uff0c\u4e5f\u5c31\u662f4\u4e2a\u5b57\u8282\u3002\u540c\u740664\u4f4d\u7f16\u8bd1\u5668\uff09<\/code><\/div>\n
    <\/code>short<\/code> int<\/code> : 2\u4e2a\u5b57\u8282<\/code><\/div>\n
    <\/code>int<\/code>\uff1a 4\u4e2a\u5b57\u8282<\/code><\/div>\n
    <\/code>unsigned <\/code>int<\/code> : 4\u4e2a\u5b57\u8282<\/code><\/div>\n
    <\/code>float<\/code>: 4\u4e2a\u5b57\u8282<\/code><\/div>\n
    <\/code>double<\/code>: 8\u4e2a\u5b57\u8282<\/code><\/div>\n
    <\/code>long<\/code>: 4\u4e2a\u5b57\u8282<\/code><\/div>\n
    <\/code>long<\/code> long<\/code>: 8\u4e2a\u5b57\u8282<\/code><\/div>\n
    <\/code>unsigned <\/code>long<\/code>: 4\u4e2a\u5b57\u8282<\/code><\/div>\n
    64\u4f4d\u7f16\u8bd1\u5668\uff1a64\u4f4d\u7cfb\u7edf\u4e0b\u6307\u9488\u5360\u75288\u5b57\u8282<\/code><\/div>\n
    <\/code>char<\/code> \uff1a1\u4e2a\u5b57\u8282<\/code><\/div>\n
    <\/code>char<\/code>*(\u5373\u6307\u9488\u53d8\u91cf): 8\u4e2a\u5b57\u8282<\/code><\/div>\n
    <\/code>short<\/code> int<\/code> : 2\u4e2a\u5b57\u8282<\/code><\/div>\n
    <\/code>int<\/code>\uff1a 4\u4e2a\u5b57\u8282<\/code><\/div>\n
    <\/code>unsigned <\/code>int<\/code> : 4\u4e2a\u5b57\u8282<\/code><\/div>\n
    <\/code>float<\/code>: 4\u4e2a\u5b57\u8282<\/code><\/div>\n
    <\/code>double<\/code>: 8\u4e2a\u5b57\u8282<\/code><\/div>\n
    <\/code>long<\/code>: 8\u4e2a\u5b57\u8282<\/code><\/div>\n
    <\/code>long<\/code> long<\/code>: 8\u4e2a\u5b57\u8282<\/code><\/div>\n
    <\/code>unsigned <\/code>long<\/code>: 8\u4e2a\u5b57\u8282<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

     <\/p>\n

      \n
    • \n
      \n
      \n
      \u9884\u5907\u77e5\u8bc6\uff1a\u57fa\u672c\u7c7b\u578b\u5360\u7528\u5b57\u8282<\/div>\n
      \u572832\u4f4d\u64cd\u4f5c\u7cfb\u7edf\u548c64\u4f4d\u64cd\u4f5c\u7cfb\u7edf\u4e0a\uff0c\u57fa\u672c\u6570\u636e\u7c7b\u578b\u5206\u522b\u5360\u591a\u5c11\u5b57\u8282\u5462\uff1f<\/div>\n
      <\/div>\n
      32\u4f4d\u64cd\u4f5c\u7cfb\u7edf\uff1a<\/div>\n
      <\/div>\n
      char : 1 int \uff1a4 short : 2 unsigned int : 4 long : 4 unsigned long : 4 long long : 8 float : 4 double : 8 \u6307\u9488 : 4<\/div>\n
      <\/div>\n
      64\u4f4d\u64cd\u4f5c\u7cfb\u7edf<\/div>\n
      <\/div>\n
      char : 1 int \uff1a4 short : 2 unsigned int : 4 long : 8 unsigned long : 8 long long : 8 float : 4 double : 8 \u6307\u9488 : 8<\/div>\n
      <\/div>\n
      \u5185\u5b58\u5bf9\u9f50\uff1a<\/div>\n
      \u6210\u5458\u5bf9\u9f50\u6709\u4e00\u4e2a\u91cd\u8981\u7684\u6761\u4ef6\uff0c\u5373\u6bcf\u4e2a\u6210\u5458\u6309\u81ea\u5df1\u7684\u65b9\u5f0f\u5bf9\u9f50\u3002\u5176\u5bf9\u9f50\u7684\u89c4\u5219\u662f\uff1a\u6bcf\u4e2a\u6210\u5458\u6309\u5176\u7c7b\u578b\u7684\u5bf9\u9f50\u53c2\u6570(\u901a\u5e38\u662f\u8fd9\u4e2a\u7c7b\u578b\u7684\u5927\u5c0f)\u548c\u6307\u5b9a\u5bf9\u9f50\u53c2\u6570(\u8fd9\u91cc\u9ed8\u8ba4\u662f8\u5b57\u8282)\u4e2d\u8f83\u5c0f\u7684\u4e00\u4e2a\u5bf9\u9f50\u3002\u5e76\u4e14\u7ed3\u6784\u7684\u957f\u5ea6\u5fc5\u987b\u4e3a\u6240\u7528\u8fc7\u7684\u6240\u6709\u5bf9\u9f50\u53c2\u6570\u7684\u6574\u6570\u500d\u3002\u4e0d\u591f\u5c31\u8865\u7a7a\u5b57\u8282\u3002<\/div>\n
      <\/div>\n
      \u4e3e\u4f8b\uff1a<\/div>\n
      <\/div>\n
      \u590d\u5236\u4ee3\u7801<\/div>\n
      struct t{<\/div>\n
      long a;<\/div>\n
      short b;<\/div>\n
      int c;<\/div>\n
      int *d;<\/div>\n
      char e;<\/div>\n
      }<\/div>\n
      \u590d\u5236\u4ee3\u7801<\/div>\n
      <\/div>\n
      <\/div>\n
      \u572864\u4f4d\u64cd\u4f5c\u7cfb\u7edf\u4e2d\u7684\u5927\u5c0f\u3002<\/div>\n
      <\/div>\n
      \u5206\u6790\uff1a<\/div>\n
      <\/div>\n
      \u6309\u7167\u58f0\u660e\u7684\u987a\u5e8f\u4e00\u4e2a\u4e00\u4e2a\u5206\u914d\u5185\u5b58\u7a7a\u95f4\u3002<\/div>\n
      <\/div>\n
      \u9996\u5148 long \u578b\u53d8\u91cfa\uff0c\u572864\u4f4d\u5730\u5740\u7a7a\u95f4\u4e2d\uff0clong\u578b\u53608\u4e2a\u5b57\u8282\uff0c\u6240\u4ee5\u6309\u7167\u4e0a\u9762\u7684\u5bf9\u9f50\u6761\u4ef6\uff0c\u8fd9\u4e2a\u6210\u5458\u5e94\u8be5\u6309\u7167\u5bf9\u5176\u53c2\u6570 min(sizeof(long), 8) = 8\u5b57\u8282\u6765\u5bf9\u9f50\uff0c\u6240\u4ee5\u628a\u8fd9\u4e2a\u6210\u5458\u5b58\u653e\u5728 0~7 \u5185\u5b58\u5355\u5143\u4e2d\u3002<\/div>\n
      <\/div>\n
      \u7136\u540e short\u578b\u53d8\u91cfb\uff0c\u572864\u4f4d\u5730\u5740\u7a7a\u95f4\u4e2d\uff0cshort\u578b\u53602\u4e2a\u5b57\u8282\uff0c\u6240\u4ee5\u6309\u7167\u4e0a\u9762\u7684\u5bf9\u9f50\u6761\u4ef6\uff0c\u8fd9\u4e2a\u6210\u5458\u5e94\u8be5\u6309\u7167\u5bf9\u5176\u53c2\u6570 min(sizeof(short), 8) = 2\u5b57\u8282\u6765\u5bf9\u9f50\uff0c\u6240\u4ee5\u628a\u8fd9\u4e2a\u6210\u5458\u5b58\u653e\u5728 8~9 \u5185\u5b58\u5355\u5143\u4e2d\u3002<\/div>\n
      <\/div>\n
      \u7136\u540e int\u578b\u53d8\u91cfc\uff0c\u572864\u4f4d\u5730\u5740\u7a7a\u95f4\u4e2d\uff0cint\u578b\u53604\u4e2a\u5b57\u8282\uff0c\u6240\u4ee5\u6309\u7167\u4e0a\u9762\u7684\u5bf9\u9f50\u6761\u4ef6\uff0c\u8fd9\u4e2a\u6210\u5458\u5e94\u8be5\u6309\u7167\u5bf9\u5176\u53c2\u6570 min(sizeof(int), 8) = 4\u5b57\u8282\u6765\u5bf9\u9f50\uff0c\u6240\u4ee5\u628a\u8fd9\u4e2a\u6210\u5458\u5b58\u653e\u5728 12~15 \u5185\u5b58\u5355\u5143\u4e2d\uff0810\uff0c11\u5355\u5143\u90fd\u4e0d\u80fd\u88ab4\u6574\u9664\uff09\u3002<\/div>\n
      <\/div>\n
      \u7136\u540e int*\u578b\u53d8\u91cfd\uff0c\u572864\u4f4d\u5730\u5740\u7a7a\u95f4\u4e2d\uff0c\u6307\u9488\u578b\u53608\u4e2a\u5b57\u8282\uff0c\u6240\u4ee5\u6309\u7167\u4e0a\u9762\u7684\u5bf9\u9f50\u6761\u4ef6\uff0c\u8fd9\u4e2a\u6210\u5458\u5e94\u8be5\u6309\u7167\u5bf9\u5176\u53c2\u6570 min(sizeof(int*), 8) = 8\u5b57\u8282\u6765\u5bf9\u9f50\uff0c\u6240\u4ee5\u628a\u8fd9\u4e2a\u6210\u5458\u5b58\u653e\u5728 16~23 \u5185\u5b58\u5355\u5143\u4e2d\u3002<\/div>\n
      <\/div>\n
      \u7136\u540e char\u578b\u53d8\u91cfe\uff0c\u572864\u4f4d\u5730\u5740\u7a7a\u95f4\u4e2d\uff0cchar\u578b\u53601\u4e2a\u5b57\u8282\uff0c\u6240\u4ee5\u6309\u7167\u4e0a\u9762\u7684\u5bf9\u9f50\u6761\u4ef6\uff0c\u8fd9\u4e2a\u6210\u5458\u5e94\u8be5\u6309\u7167\u5bf9\u5176\u53c2\u6570 min(sizeof(char), 8) = 1\u5b57\u8282\u6765\u5bf9\u9f50\uff0c\u6240\u4ee5\u628a\u8fd9\u4e2a\u6210\u5458\u5b58\u653e\u5728 24 \u5185\u5b58\u5355\u5143\u4e2d\u3002<\/div>\n
      <\/div>\n
      \u7136\u540e\u6574\u4e2a\u7ed3\u6784\u4f53\u7684\u957f\u5ea6\u5fc5\u987b\u4e3a\u6240\u6709\u5bf9\u9f50\u53c2\u6570\u7684\u6574\u6570\u500d\uff0c\u5f53\u524d\u957f\u5ea6\u4e3a25\uff0c\u4e0d\u662f\u6240\u6709\u5bf9\u9f50\u53c2\u6570\u6574\u6570\u500d\uff0c\u5fc5\u987b\u8c03\u6574\u4e3a32\uff0c\u624d\u662f\u6240\u6709\u53c2\u6570\u6574\u6570\u500d\u3002<\/div>\n
      <\/div>\n
      \u6240\u4ee5\u8fd9\u4e2a\u7ed3\u6784\u4f53\u7684\u957f\u5ea6\u4e3a32\u3002<\/div>\n
      <\/div>\n
      <\/div>\n
      <\/div>\n
      \u5982\u679c\u7ed3\u6784\u4f53\u4e2d\u51fa\u73b0\u5b50\u7ed3\u6784\u4f53\u600e\u4e48\u529e\uff1f\u6211\u4eec\u5728\u786e\u5b9a\u5b50\u7ed3\u6784\u4f53\u7684\u5bf9\u9f50\u53c2\u6570\u65f6\uff0c\u5e94\u8be5\u5c31\u662f\u5b83\u7684\u6240\u6709\u6210\u5458\u4f7f\u7528\u7684\u5bf9\u9f50\u53c2\u6570\u4e2d\u6700\u5927\u7684\u4e00\u4e2a\u3002<\/div>\n
      <\/div>\n
      \u4e3e\u4f8b\uff1a<\/div>\n
      <\/div>\n
      \u590d\u5236\u4ee3\u7801<\/div>\n
      struct t{<\/div>\n
      char a;<\/div>\n
      int b;<\/div>\n
      };<\/div>\n
      struct s{<\/div>\n
      char c;<\/div>\n
      struct t d;<\/div>\n
      char e;<\/div>\n
      };<\/div>\n
      \u590d\u5236\u4ee3\u7801<\/div>\n
      \u572832\u4f4d\u64cd\u4f5c\u7cfb\u7edf\u4e0b\u7684\u957f\u5ea6\u3002<\/div>\n
      <\/div>\n
      \u9996\u5148\u786e\u5b9at\u7684\u5927\u5c0f\u4e3a8\uff0c\u5b83\u7684\u6240\u6709\u6210\u5458\u4f7f\u7528\u7684\u5bf9\u9f50\u53c2\u6570\u6700\u5927\u4e3a4\u3002<\/div>\n
      <\/div>\n
      \u518d\u8003\u5bdfs\uff1a<\/div>\n
      <\/div>\n
      \u9996\u5148 char \u578b\u53d8\u91cfc\uff0c\u572832\u4f4d\u5730\u5740\u7a7a\u95f4\u4e2d\uff0cchar\u578b\u53601\u4e2a\u5b57\u8282\uff0c\u6240\u4ee5\u6309\u7167\u4e0a\u9762\u7684\u5bf9\u9f50\u6761\u4ef6\uff0c\u8fd9\u4e2a\u6210\u5458\u5e94\u8be5\u6309\u7167\u5bf9\u5176\u53c2\u6570 min(sizeof(char), 8) = 1\u5b57\u8282\u6765\u5bf9\u9f50\uff0c\u6240\u4ee5\u628a\u8fd9\u4e2a\u6210\u5458\u5b58\u653e\u5728 0 \u5185\u5b58\u5355\u5143\u4e2d\u3002<\/div>\n
      <\/div>\n
      \u7136\u540e struct t\u578b\u53d8\u91cfd\uff0c\u572832\u4f4d\u5730\u5740\u7a7a\u95f4\u4e2d\uff0cstruct t\u53608\u4e2a\u5b57\u8282\uff0c\u6240\u4ee5\u6309\u7167\u4e0a\u9762\u7684\u5bf9\u9f50\u6761\u4ef6\uff0c\u8fd9\u4e2a\u6210\u5458\u5e94\u8be5\u6309\u7167\u5bf9\u5176\u53c2\u6570 4 \u5b57\u8282\u6765\u5bf9\u9f50\uff0c\u6240\u4ee5\u628a\u8fd9\u4e2a\u6210\u5458\u5b58\u653e\u5728 4~11 \u5185\u5b58\u5355\u5143\u4e2d\u3002<\/div>\n
      <\/div>\n
      \u7136\u540e char\u578b\u53d8\u91cfe\uff0c\u572832\u4f4d\u5730\u5740\u7a7a\u95f4\u4e2d\uff0cchar\u578b\u53601\u4e2a\u5b57\u8282\uff0c\u6240\u4ee5\u6309\u7167\u4e0a\u9762\u7684\u5bf9\u9f50\u6761\u4ef6\uff0c\u8fd9\u4e2a\u6210\u5458\u5e94\u8be5\u6309\u7167\u5bf9\u5176\u53c2\u6570 min(sizeof(char), 8) = 1\u5b57\u8282\u6765\u5bf9\u9f50\uff0c\u6240\u4ee5\u628a\u8fd9\u4e2a\u6210\u5458\u5b58\u653e\u5728 12 \u5185\u5b58\u5355\u5143\u4e2d\u3002<\/div>\n
      <\/div>\n
      \u7136\u540e\u6574\u4e2a\u7ed3\u6784\u4f53\u7684\u957f\u5ea6\u5fc5\u987b\u4e3a\u6240\u6709\u5bf9\u9f50\u53c2\u6570\u7684\u6574\u6570\u500d\uff0c\u5f53\u524d\u957f\u5ea6\u4e3a13\uff0c\u4e0d\u662f\u6240\u6709\u5bf9\u9f50\u53c2\u6570\u6574\u6570\u500d\uff0c\u5fc5\u987b\u8c03\u6574\u4e3a16\uff0c\u624d\u662f\u6240\u6709\u53c2\u6570\u6574\u6570\u500d\u3002<\/div>\n
      <\/div>\n
      \u6240\u4ee5\u6b64\u7ed3\u6784\u4f53\u5927\u5c0f\u4e3a16.<\/div>\n<\/div>\n<\/div>\n<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"

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