ACM分数转小数

#include <cstdio>
int main (void)
{
    long long a,b;
    int c;
    while (scanf ("%lld%lld%d",&a,&b,&c) == 3 && !(a == 0 && b == 0 && c == 0))
    {
        printf ("%lld.",a/b);//先输出整数部分和小数点
        a %= b;
        for (int i = 1; i < c; i++)
        {
            printf ("%lld",a*10/b);
            a = a*10%b;
        }
        if (a*10%b*10/b < 5)//对需要输出的最后一位进行是否进位的判断
            printf ("%lld",a*10/b);
        else
            printf ("%lld",a*10/b+1);
    }
    return 0;
    
}