#include <stdio.h>
int main()
{
int n,m;
printf("输入十进制数:");
scanf("%d",&n);
printf("输入转换的进制数:");
scanf("%d",&m);
int s,ys,er,i;
if(m==2){
while(n!=0)                              我想问一下如果用for循环替代while怎么写
{
n=n/2;                        
ys=n%2;
er=+ys*i;
i=i*10;                                                              
}
printf("%d进制数为：%llu",m,er);
return 0;
}

}

[此贴子已经被作者于2021-4-18 23:27编辑过]

最简单的就是把while那行改成for (; n > 0;)
你的算法也有问题。

//进制转换
#include <stdio.h>
int main()
{
    int n, m;
    printf("输入十进制数:");
    scanf("%d", &n);
    printf("输入转换的进制数:");
    scanf("%d", &m);
    int ys;
    unsigned long long er = 0, i = 1;
    if (m == 2)
    {
        while (n != 0) //我想问一下如果用for循环替代while怎么写
        {
            ys = n % 2;
            er += ys * i;
            i = i * 10;
            n = n / 2;
        }

        printf("\n%d进制数为：%llu\n", m, er);
    }
    system("pause");
    return 0;
}