Java基础方法递归

public class RecursionTest03{
  public static void main(String[] args){
    //1~80的和
    int n = 80;
    int reValue = sum(n);
    System.out.println("reValue = " + reValue);
  }
  public static int sum(int n){
    //4 + 3 + 2 + 1
    if(n == 1){
      return 1;
    }
    return n + sum(n - 1);
  }
}
//n + sum(n-1)
//4 + sum(3)
//4 + 3 + 2 + sum(1)
//4 + 3 + 2 + 1

public class RecursionTest04{
  public static void main(String[] args){
  int n = 5;
  int reValue = method(n);
  System.out.println("reValue = " + reValue);
  }
  public static int method(int n){
  if(n == 1){
    return 1;
  }
  return n*method(n-1);
  } 
}