求階乘，輸入一個正整數 n，輸出n！

#include<stdio.h>
int factorial (int n);

int main(){
int n;

scanf("%d",&n);
printf("%d \n",factorial(n));

return 0;
}

int factorial(int n){

int i,fact=1;

for(i=1;i<=n;i++)
fact = fact*i;

return fact;

}