面试笔试问题总结（一）—位制、位操作、位图

#include<stdio.h>
#include<stdlib.h>

int main(){
    unsigned char uint8 = 0;
    signed char int8 = 0;
    unsigned short uint16 = 0;
    signed short int16 = 0;
    unsigned int uint32 = 0;
    signed int int32 = 0;
    float fp32 = 0;
    double fp64 = 0;
    unsigned long ulong = 0;
    printf("unsigned char is %d bit\n\r", sizeof(uint8)*8);
    printf("signed char is %d bit\n\r", sizeof(int8)*8);
    printf("unsigned short is %d bit\n\r", sizeof(uint16)*8);
    printf("signed short is %d bit\n\r", sizeof(int16)*8);
    printf("unsigned int is %d bit\n\r", sizeof(uint32)*8);
    printf("signed int is %d bit\n\r", sizeof(int32)*8);
    printf("float fp32 is %d bit\n\r", sizeof(fp32)*8);
    printf("double fp64 is %d bit\n\r", sizeof(fp64)*8);
    printf("unsigned long is %d bit\n\r", sizeof(ulong)*8);
    system("pause");
    return 0;
}

32位编译器：

      char ：1个字节
      char*（即指针变量）: 4个字节（32位的寻址空间是2^32, 即32个bit，也就是4个字节。同理64位编译器）
      short int : 2个字节
      int：  4个字节
      unsigned int : 4个字节
      float:  4个字节
      double:   8个字节
      long:   4个字节
      long long:  8个字节
      unsigned long:  4个字节

  64位编译器：

      char ：1个字节
      char*(即指针变量): 8个字节
      short int : 2个字节
      int：  4个字节
      unsigned int : 4个字节
      float:  4个字节
      double:   8个字节
      long:   8个字节
      long long:  8个字节
      unsigned long:  8个字节