Recursive calculation

Recursive calculation

package Recurison;/*
 *@author wanghongyuan
 *@Create 2021/1/9 22:09
 */

public class Demo02Recurison {
    
    
    public static void main(String[] args) {
    
    
        int s = sum(3);
        System.out.println(s);;

    }

    private static int sum(int n) {
    
    
        if (n ==1){
    
    
            return 1;
        }

        // 获取下一个被加的数字（n-1）
        return n+(sum(n-1));
    }

}

Principle of Recursion