习题2-18求组合数include<stdio.h>double fact( int n);double fact(int n){ double z=1.0; int i; for(i=1;i<=n;i++) z=z*i; return(z);}int main(){ int m,n; double C; printf("请输入两个整数m,n\n"); scanf("%d %d",&m,&n); if(m<=n) { C=fact(n)/(fact(m)*fact(n-m)); printf(" result=%.0f\n",C); } else printf("输入错误"); return 0;}