C 求n的階乘

1.題目

遞歸和非遞歸分別實現求n的階乘

2.程序代碼

#define _CRT_SECURE_NO_WARNINGS 1

#include <stdio.h>
#include <Windows.h>

int factorial1(int num)//非遞歸方式求n的階乘
{
    int i = 0;
    int count = 1;

    for (i = 1; i <= num; i++)
    {
        count *= i;
    }
    return count;
}

int factorial2(int num)//遞歸方式求n的階乘
{
    if (num == 1)
    {
        return 1;
    }
    return num * factorial2(num - 1);
}

int main()
{
    int num = 0;

    printf("please input a num:");
    scanf("%d", &num);

    printf("%d\n", factorial1(num));
    printf("%d\n", factorial2(num));

    system("pause");
    return 0;
}

3.執行結果