Java递归求 1 + 2 + 3 + ... + 10

 public static int retSum(int n) {
        //递归求 1 + 2 + 3 + ... + 10
        if (n == 1) {
            return 1;
        }
        return n + retSum(n-1);
    }
    public static void main(String[] args) {
        System.out.println(retSum(10));
    }

输出结果：