2017-11-11

Program：

求解:1+2!+3!+...+n!的和。

代码如下：

/*
 * 求解:1+2!+3!+...+n!的和
 * 
 * Date Written:2017-11-11
 * 
 * */

package test;

import java.util.Scanner;

public class TestDemo {
    
    public static void main(String args[]) {
        
        int n = 0;                //接受用户输入，定义求解到最大数的阶乘
        Scanner scan = new Scanner(System.in);
        
        System.out.println( "Please input the value of n:" );
        n = scan.nextInt();       //取得用户输入
        
        System.out.println( "The result is " + getResult(n) );
        
        scan.close();            //关闭scan;
            
    }
    
    //求解阶乘
    public static int getResult(int n) {
        
        int sum = 0;             //存储最终结果
        int temp = 1;            //当前i的阶乘
        for( int i = 1; i <= n; i++) {
            
            temp *= i;
            sum += temp;
        }
        
        return sum;
    }
    
    
}