#includeint y;void fac(int n){if(n==1){y=1;return;} //1!=1 fac(n-1); //当n>1时，递归计算(n-1)! y*=n; //计算出n!}int main(){int n; scanf("%d",&n); fac(n); printf("%d!=%d\n",n,y); return 0; }
