C语言计算1!+2!+3!+...+20!的和

#include <stdio.h>

int main() { int i, j; long long sum = 0, fact = 1; for (i = 1; i <= 20; i++) { fact = 1; for (j = 1; j <= i; j++) { fact *= j; } sum += fact; } printf('1!+2!+3!+...+20! = %lld', sum); return 0; }