sizeof运算符返回将数据存储在内存中所需的字节

sizeof运算符将变量名称或数据类型作为参数，并返回将数据存储在内存中所需的字节数。

#include <stdio.h> 
int main()
{ 
   int x; 
   float f; 
   double d; 
   char c; 
   typedef struct employee { 
     int ID; 
     char *name; 
     float salary; 
   } e; 
   printf("\nSize of integer: %d bytes\n", sizeof(x)); 
   printf("Size of float: %d bytes\n", sizeof(f)); 
   printf("Size of double %d bytes\n", sizeof(d)); 
   printf("Size of char %d byte\n", sizeof(c)); 
   printf("Size of employee structure: %d bytes\n", sizeof(e)); 
}