linux c int、short、long、long long、unsigned、unsigned short、unsigned long、unsigned long long 长度简介

比眉伴天荒 2021-09-07 06:00 507阅读 0赞

<table> 
 <thead> 
  <tr> 
   <th>类型标识符</th> 
   <th>32位机器所占字节长度</th> 
   <th>64位机器所占字节长度</th> 
   <th>格式化输出</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>int</td> 
   <td>4</td> 
   <td>4</td> 
   <td>%d</td> 
  </tr> 
  <tr> 
   <td>short</td> 
   <td>2</td> 
   <td>2</td> 
   <td>%d</td> 
  </tr> 
  <tr> 
   <td>long</td> 
   <td>4</td> 
   <td>8</td> 
   <td>%ld</td> 
  </tr> 
  <tr> 
   <td>long long</td> 
   <td>8</td> 
   <td>8</td> 
   <td>%lld</td> 
  </tr> 
  <tr> 
   <td>unsinged</td> 
   <td>4</td> 
   <td>4</td> 
   <td>%u</td> 
  </tr> 
  <tr> 
   <td>unsinged short</td> 
   <td>2</td> 
   <td>2</td> 
   <td>%u</td> 
  </tr> 
  <tr> 
   <td>unsiged long</td> 
   <td>4</td> 
   <td>8</td> 
   <td>%lu</td> 
  </tr> 
  <tr> 
   <td>unsigned long long</td> 
   <td>8</td> 
   <td>8</td> 
   <td>%llu</td> 
  </tr> 
 </tbody> 
</table>

综上所述: 32位机器和64位机器比较，对于long和unsigned long类型，所占用的空间是不一样的，从代码可移植性考虑，  
定义变量最好明确所需长度，选用合适的变量类型。(注：这只是常见而已，并不代表所有的32位机器和64位机器均是这样，所以选用比较明确的类型，更合理高效)

#include <stdio.h>
    #include <stdlib.h>
    
    int main()
    {
    	int i_a = 1;
    	short s_a = 2;
    	long l_a = 3;
    	long long ll_a = 4;
    	unsigned u_a = 5;
    	unsigned short us_a = 6;
    	unsigned long ul_a = 7;
    	unsigned long long ull_a = 8;
    
    	printf(" i_a = %d, sizeof(i_a) = %u\n", i_a, sizeof(i_a));
    	printf(" s_a = %d, sizeof(s_a) = %u\n", s_a, sizeof(s_a));
    	printf(" l_a = %ld, sizeof(l_a) = %u\n", l_a, sizeof(l_a));
    	printf(" ll_a = %lld, sizeof(ll_a) = %u\n", ll_a, sizeof(ll_a));
    	printf(" u_a = %u, sizeof(u_a) = %u\n", u_a, sizeof(u_a));
    	printf(" us_a = %u, sizeof(us_a) = %u\n", us_a, sizeof(us_a));
    	printf(" ul_a = %lu, sizeof(ul_a) = %u\n", ul_a, sizeof(ul_a));
    	printf(" ull_a = %llu, sizeof(ull_a) = %u\n", ull_a, sizeof(ull_a));
    
    	return 1;
    }

X86 VS测试结果:

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