递归的简易实现
public class Main {
public static void main(String args[]) {
System.out.println(sum(100));
System.out.println(sum(1000));
}
public static int sum(int num) {
if (num == 1) {
return 1;//递归的出口;
}
return num + sum(num - 1);//递归调用sum方法
}
}

更多精彩
public class Main {
public static void main(String args[]) {
System.out.println(sum(100));
System.out.println(sum(1000));
}
public static int sum(int num) {
if (num == 1) {
return 1;//递归的出口;
}
return num + sum(num - 1);//递归调用sum方法
}
}