c语言中输出十进制数转换为二进制数后包含1的数目

c语言中输出十进制数转换为二进制数后包含1的数目

1、

#include <stdio.h>

int main(void)
{
    unsigned a;
    puts("please input a nonnegative integers.");
    printf("a = "); scanf("%u", &a);
    
    int n = 0;
    while(a)
    {
        if(a & 1U)
            n++;
        a >>= 1;
    }
    printf("the number of 1 in a: %u
", n);
    
    return 0;
}

2、函数版

#include <stdio.h>

int count_bits(unsigned x)
{
    int bits = 0;
    while(x)
    {
        if(x & 1U)
            bits++;
        x >>= 1;
    }
    return bits;
}

int main(void)
{
    unsigned a, b, c;
    puts("please input three nonnegative integers.");
    printf("a = "); scanf("%u", &a);
    printf("b = "); scanf("%u", &b);
    printf("c = "); scanf("%u", &c);
    
    printf("the number of 1 in a: %d
", count_bits(a));
    printf("the number of 1 in b: %d
", count_bits(b));
    printf("the number of 1 in c: %d
", count_bits(c));
    
    return 0;
}