用c语言求 1!+2!+3!+4!+5!+…+15！

可以使用for循环或者while循环来实现1!+2!+3!+4!+5!+…+15！的累加。具体代码如下：

方法一：使用for循环

#include <stdio.h>

int main()
{
    int i, n;
    long long sum = 0, factorial = 1;

    printf("请输入N的值：");
    scanf("%d", &n);

    for (i = 1; i <= n; i++) {
        factorial *= i;
        sum += factorial;
    }

    printf("1!+2!+3!+...+%d! = %lld\n", n, sum);

    return 0;
}

方法二：使用while循环

#include <stdio.h>

int main()
{
    int i = 1, n;
    long long sum = 0, factorial = 1;

    printf("请输入N的值：");
    scanf("%d", &n);

    while (i <= n) {
        factorial *= i;
        sum += factorial;
        i++;
    }

    printf("1!+2!+3!+...+%d! = %lld\n", n, sum);

    return 0;
}