C语言计算 ∑𝑛𝑚=1 𝑚! 的值 (0 < n <= 20)

#include <stdio.h>

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

int main() { int n; printf("请输入一个数n："); scanf("%d", &n);

int sum = 0;
for (int m = 1; m <= n; m++) {
    sum += factorial(m);
}

printf("∑𝑛𝑚=1 𝑚!的值为：%d\n", sum);

return 0;

}