CODEWITHSUNDEEP
javarecursion
dbconfession
dbconfession

Reputation: 1199

Java How do I output the initial value of a method's variable before it enters the first recursion of the method?

Any idea on how to print the initial variable used in the classic factorial recursion? Here's what I have.

public class factorial{
  public static void main(String[] args){
    System.out.println("Output:" + initialN(factorial(4))); 
    System.out.println("Answer:24");
  }

  public static int factorial(int n){
    if(n == 1){
      return 1;
    }
    else{
      return n*(n-1);
    }
  }

  public static int initialN(int n){
    int init = n;
    System.out.println("N:" + init); return init;
  }
}

Right now my output looks like this:

N:24
Output:24
Answer:24

But I'm trying to have it show only what n is initially before it enters the second iteration of the factorial method. So N should be showing as 4, not 24. Thanks in advance.

Upvotes: 0

Views: 141

Answers (2)

Brady Sheehan
Brady Sheehan

Reputation: 162

You just need to change this line:

System.out.println("Output:" + factorial(initialN(4)));

You should call initialN() inside factorial because the methods are executed from within and then outward.

As a side note, I would write it like this: 

public static int factorial3(int num){ 
if(num == 0)
  return 1;
else{
  if(i==0) \\ i is global variable initialized to zero
   System.out.println("N:" + num);
  i++;
  return num * factorial3(num-1);
  }
}

and call it like this:

System.out.println(factorial3(4));

Upvotes: 3

dbconfession
dbconfession

Reputation: 1199

I got it. If you call the recursion method from a another method, you can print the initial variable. here is my solution. I'd be interested to see if anyone has a more simple solution.

public class factorial{
  public static void main(String[] args){
    System.out.println("Output:" + (factorial(3))); System.out.println("Answer:6");
    System.out.println("Output:" + (factorial(4))); System.out.println("Answer:24");
    System.out.print("--------------------");
  }     

  public static int factorial(int n){
    System.out.println("--------------------\nN:" + n);
    return factorial2(n);
  }

  public static int factorial2(int n){
    if(n == 1){
    return 1;
    }
    else{
      return n*factorial2(n-1);
    }
  }
}

Upvotes: 0

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