c++ 典型循环:s=1!+2!+3!+……+n!,用三种循环编程

1. 使用for循环

#include <stdio.h>

int main() {
    int n, s = 1;
    printf("请输入n：");
    scanf("%d", &n);
    for(int i=1; i<=n; i++) {
        int fact = 1;
        for(int j=1; j<=i; j++) {
            fact *= j;
        }
        s *= fact;
    }
    printf("s = %d\n", s);
    return 0;
}

2. 使用while循环

#include <stdio.h>

int main() {
    int n, i = 1, s = 1;
    printf("请输入n：");
    scanf("%d", &n);
    while(i <= n) {
        int j = 1, fact = 1;
        while(j <= i) {
            fact *= j;
            j++;
        }
        s *= fact;
        i++;
    }
    printf("s = %d\n", s);
    return 0;
}

3. 使用do-while循环

#include <stdio.h>

int main() {
    int n, i = 1, s = 1;
    printf("请输入n：");
    scanf("%d", &n);
    do {
        int j = 1, fact = 1;
        do {
            fact *= j;
            j++;
        } while(j <= i);
        s *= fact;
        i++;
    } while(i <= n);
    printf("s = %d\n", s);
    return 0;
}