剑指 Offer 64. 求1+2+…+n

package leetcode;

public class offer_64 {
    public int sumNums(int n) {
        //&&预算符左边为false，则不会判断右边直接返回false
        boolean flag=n>0&&(n=n+sumNums(n-1))>0;
        return n;
        
    }
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        offer_64 off=new offer_64();
        System.out.println(off.sumNums(3));
    }

}