求1！+2！+3！+...+20!,自定义函数fact在main函数中调用

Answer 1

public static void main(String[] args) {
private final static int MAX = 20;
int num=1;
int sum=0;
for(int i=1;i<=MAX;i++) {
num*=i;//算阶乘
sum+=num;//累加各数的阶乘
}
System.out.println(sum);//输出结果
}

Answer 2

#include<iostream>
using namespace std;
const int MAX =20;
int main()
{
int num=1;
int sum=0;
for(int i=1;i<=MAX;i++)
{
num*=i;//算阶乘
sum+=num;//累加各数的阶乘
}
cout<<sum<<endl;
}

Answer 3

#include<iostream>
using namespace std;
const int MAN =20;
int main()
{
int num=1,sum=0,i;
for(i=1;i<=MAN;i++)
{
num*=i;
sum+=num;
}
cout<<sum<<endl;
system("pause");
return 0;
}

Answer 4

还是比较喜欢用递归

Answer 5

long f(int n)
{ if (n==1) return 1;
else return n*f(n-1);

}

long fact(int n)
{ if (n==0) return 0;
else return fact(n-1)+f(n);
}

void main()
{ printf("%l",fact(20);
return;
}