Java之递归求和的两张方法

package com.smbea.demo;

public class Student {
	private int sum = 0;

	
	/**
	 * 递归求和
	 * @param num
	 */
	public void sum(int num) {
		this.sum += num--;
		
		if(0 < num){
			sum(num);
		} else {
			System.out.println("sum = " + sum);
		}
	}
	
}

package com.smbea.demo;

public class Test {

	public static void main(String[] args) {
		Teacher teacher = new Teacher();
		teacher.sum();
	}

	public static int sum(int num){
		if(1 == num){
			return 1;
		} else {
			return num + sum(num - 1);
		}
	};
}