c 递归与for循环分别求n的阶乘

#include <stdio.h>

int factorial(int n) {
    if (n == 0) return 1;
    else return n * factorial(n - 1);
}

int main() {
    int n; scanf("%d",&n);
    printf("%d\n",factorial(n));
    return 0;
}

#include <stdio.h>

int main(){
    int n;
    while(scanf("%d", &n) != EOF){
        if(n < 0 || n > 20){
            printf("input error!\n");
            continue;//思考下这里如果换成break输出会有什么变化
        }
        long long result = 1;
        for(int i = 1; i <= n; i++)
            result *= i;
        printf("%lld\n", result);
    }
    return 0;
}