Unable to Return Variable

[Jared Osborne]

This program's supposed your typical random number generator. It doesn't seem to be passing the int Number back from the NumbertoGuess method for use in the rest of the program. What am I doing wrong here? I'm aware there are some missing things in this program, I'm concerned about getting the value returned properly right now.

    import java.util.*;  //for scanner

public class Errorhandling {

    public static void main(String[]args){
    Scanner console = new Scanner(System.in);
    Haiku();
    int Number = 0;
    int YorN = 1;    
    int GuessNum = 1;
    int BestGuess = 0;
    int MxNumb = 20;
    while(YorN != 0){
    NumbertoGuess(Number, MxNumb);
    MyGuess(Number, GuessNum);
    BestGame(BestGuess, GuessNum);
    PlayitAgain(GuessNum, YorN);
    }
    }
    
    public static void Haiku(){
        System.out.println("This is a fun game");
        System.out.println("You get to guess my number");
        System.out.println("I wish you good luck");
    }
    
    public static int NumbertoGuess(int Number, int MxNumb){
            Random R = new Random();
            Number = R.nextInt(MxNumb) + 1;
            System.out.println(Number);
            System.out.println("I'm thinking of a number between 1 and " + MxNumb + "...");
            return Number;
    }
    
    public static int MyGuess(int Number, int GuessNum){
        Scanner console = new Scanner(System.in);
            int Guess = console.nextInt();
            while (Guess != Number){
                if(Guess < Number){
                    System.out.println("It's Higher.");
                    GuessNum++;
                    Guess = console.nextInt();
                } else if(Guess > Number){
                    System.out.println("It's Lower.");
                    GuessNum++;
                    Guess = console.nextInt();
                } else {
                }    
    }    return GuessNum;
    }
    
    public static int BestGame(int GuessNum, int BestGuess){
        if(BestGuess > GuessNum){
          BestGuess = GuessNum;
        return BestGuess;    
    }    return BestGuess;
    }
    
    public static int PlayitAgain(int GuessNum, int YorN){
        Scanner console = new Scanner(System.in);
        System.out.println("You got it right in " + GuessNum + " guesses");
        System.out.println("Do you want to play again?");
        int playAgain = 0;
        playAgain = console.nextInt();
        /*playAgain.toUpperCase();
        playAgain.charAt(0);**/
        if(playAgain == 1){
            YorN = 1;
        } else if(playAgain == 0){
            YorN = 0;
        } else { 
        System.out.println("I didn't understand what you meant, that must mean you want to play again!");
            YorN = 1;
}    return YorN; 
}
}

[Saifuddin Merchant]

Nothing looks wrong with NumbertoGuess. It is returning the number.

The question is - What makes you think that its not returning a number?

[Jared Osborne]

Thanks for the help, Sam.

I've been doing some debugging with Ststem.out.println and trying to track the variables and their values as the program runs. If you execute the code, it will let you pick a number but will always tell you the number is lower than your guess. When you guess either a 0 or guess twice, it says you've guessed correctly and asks if you'd like to play again.

Far as I can tell, it's not passing the randomized Number variable back into the public void main for use in the next method in the series once it's generated in NumbertoGuess. I see the number generated correctly within NumbertoGuess but always see a value of 0 with a println at line 15 or 16 when I check it.

[Joanne Neal]

Java is pass by value, so passing Number as a parameter to the method will not cause Number to be changed.
What you should have is

Number = NumbertoGuess(MxNumb);   
.
.
.       
public static int NumbertoGuess(int MxNumb){   
  Random R = new Random();   
  int num = R.nextInt(MxNumb) + 1;   
  System.out.println(num);   
  System.out.println("I'm thinking of a number between 1 and " + MxNumb + "...");   
  return num;   
} 

Note that I've changed the name of the variable in NumbertoGuess to make it obvious that it is not the same variable as the Number instance variable

[Jared Osborne]

Alright, that makes sense. So how do I get the value of num out of the method for use in the rest of the program? Does the returning of num pass that value as the int num or back to NumbertoGuess?

[Eric Mission]

Your have several problems with this code...

1 You don't adhere to Sun's naming recommendations.

Sun Naming Conventions

2. Read this article to understand pass-by-value and pass-by-reference for Java.

Java parameter passing

The third issue is a result of trying to manipulate the parameter instead of capturing the return value from your method. NumbertoGuess returns a value- and you aren't storing it into anything!

public static void main(String args[]) {
    int sum = -1; //CREATE VARIABLE

    sum = add(args[0], args[1]); //CAPTURE RETURN VALUE FROM CALLING METHOD

    System.out.println(sum); //PRINT TO SCREEN
}

public static int add(int first, int second) {
   return first + second;
}

[Eric Mission]

Ooppss, sry Joanne! This rotten connection is so sloooow (didn't see your post) I might as well have mailed in my post-

[Jared Osborne]

That's what I get for going from a pass-by-reference language like VB to Java. lol

I'll mess around with it for a bit and see what I come up with. Thanks for the help!

[Joanne Neal]

Jared Osborne wrote:Alright, that makes sense. So how do I get the value of num out of the method for use in the rest of the program?

Thats what the line 'return num;' does.

Jared Osborne wrote:Does the returning of num pass that value as the int num or back to NumbertoGuess?

Note how I also changed your call to the method. The returned value will be assigned to Number

[Jared Osborne]

Workin' like a charm now. Thanks for the help, all.