#include<stdio.h>
int main()
{
    int M,N,i,j;
    double sum;
    while(scanf("%d%d",&M,&N)!=EOF)
    {
        if(M==0&&N==0) break;
        sum=1;
        for(i=M,j=1;i>=M-N+1;i--,j++)
        {
            sum=sum/j*i;
        }
        printf("%d things taken %d at a time is %.lf exactly.\n",M,N,sum);
    }
    return 0;
}

• Re:奇怪..为什么用__int64过不了,而用double就AC了,请大牛们帮看下... (29) 20055106 2007-08-14 09:18:36