计算一个字节中有多少位被置1

代码

#include <stdio.h>
#define BIT7 (0x1<<7)
int calculate(unsigned char c)
{
    int count = 0;
    int i = 0;
    unsigned char comp = BIT7;
    for(i = 0;i<sizeof(c)*8;i++)
    {
        if((c&comp)!= 0)
        {
            count++;
        }
        comp = comp>>1;
    }
    return count;
}
int main()
{
    unsigned char c = 0;
    int count = 0;
    scanf("%d",&c);   //97
    count = calculate(c);
    printf("%d\n",count);   //3
    return 0;
}