#include?<stdio.h>
int?main()
{
????puts("各種數據類型所占內存字節數\n\n");
????puts("integers:");
????printf("sizeof(char)?=?%d\n",sizeof(char));
????printf("sizeof(short?int)?=?%d\n",sizeof(short));
????printf("sizeof(int)?=?%d\n",sizeof(int));
????printf("sizeof(unsigned?int)?=?%d\n",sizeof(unsigned?int));
????printf("sizeof(long?int)?=?%d\n",sizeof(long));
????printf("sizeof(long?long?int)?=?%d\n",sizeof(long?long?));

????puts("\nfloat:");
????printf("sizeof(float)?=?%d\n",sizeof(float));
????printf("sizeof(double)?=?%d\n",sizeof(double));
????printf("sizeof(long?double)?=?%d\n",sizeof(long?double));
????printf("\npointers:\n");
????printf("sizeof(char?*)?=?%d\n",sizeof(char?*));
????printf("sizeof(int?*)?=?%d\n",sizeof(int?*));
????printf("sizeof(float?*)?=?%d\n",sizeof(float?*));
????printf("sizeof(double?*)?=?%d\n",sizeof(double?*));
????//64?bit?system
????return?0;????
}

【結果】

各種數據類型所占內存字節數


integers:
sizeof(char) = 1
sizeof(short int) = 2
sizeof(int) = 4
sizeof(unsigned int) = 4
sizeof(long int) = 8
sizeof(long long int) = 8

float:
sizeof(float) = 4
sizeof(double) = 8
sizeof(long double) = 16

pointers:
sizeof(char *) = 8
sizeof(int *) = 8
sizeof(float *) = 8
sizeof(double *) = 8