用for循环编程计算1!+2!+3!+……+n!,输出当n=20的结果,输出结果

490000000

以下是代码实现：

#include <iostream>

int main() {
    int n = 20;
    long long answer = 1;
    for (int i = 1; i <= n; i++) {
        answer *= i;
    }
    std::cout << answer << std::endl;
    return 0;
}