#include<stdio.h> int fact(int n); int fact1(int r); int main(void) { int n,r,m,nCr; printf("n r ->"); scanf("%d %d",&n,&r); m=n-r; if (n < m || n < 0 || m < 0) return printf("nCr=0\n"); nCr=fact(n)/(fact1(r)*fact(m)); printf("nCr=%d\n",nCr); return 0; }