CODEWITHSUNDEEP
java
CodeMonkey
CodeMonkey

Reputation: 2523

How can I read a number in between 2 numbers?

I am fairly new to Java and I am trying to write a small program that asks a user to enter an integer between 0-4. I have written this so far and but it doesn't seem to work! Can anyone tell me where am I wrong?

import java.util.Scanner;
public class GameCharSelect {

    public static void main(String[] argh){
        int myChar;
        Scanner in = new Scanner(System.in);
        {
            System.out.print("choose a player: ");
            myChar = in.nextInt();
        }while(myChar>0 && myChar<4);

        System.out.println("--------");
        System.out.println("you chose "+ myChar);

    }

}

Now I want the number to be 1,2 or 3 or else it loop until the user input one of these but the program accept any number at the moment. Where am I wrong?

Upvotes: 1

Views: 103

Answers (4)

Ravi K Thapliyal
Ravi K Thapliyal

Reputation: 51721

Your loop should look like

while (true) {
    System.out.print("Choose a player: ");
    myChar = in.nextInt();
    if (myChar > 0 && myChar < 4) {
        break; // out of the loop
    }
}

That is you only break; out of it if the scanned value is either 1, 2, or 3.

@Ali, while(true) approach is perfectly fine. In fact, it's far more common to see them than a do-while() in actual code running out there. The downvote received is subjective and based on individual coding style preference rather than an indication on the correctness of the answer.

Upvotes: -1

David Ruiz
David Ruiz

Reputation: 96

You haf two problems in your code:

  • You are putting the while in a wrong way, you should put a do-while statement or put the while before the {...}.
  • You also want to run the loop when you put a wrong number (<1 or >3), not when you put the correct number(between 1 and 3)... So you also need to change the expression.

My code would be something like this:

import java.util.Scanner;
public class GameCharSelect {

    public static void main(String[] argh){
        int myChar;
        Scanner in = new Scanner(System.in);
        do{
            System.out.print("choose a player: ");
            myChar = in.nextInt();
        } while(myChar<1 || myChar>3);

        System.out.println("--------");
        System.out.println("you chose "+ myChar);

    }

}

Upvotes: 1

Jite
Jite

Reputation: 5847

Your while condition is wrong.
You are checking if the char is larger than 0 AND lower than 4, and if it is, it will do the loop again, while what you are after is the oposite.
Change the statement to check if myChar is smaller than 1 OR higher than 3.
myChar < 1 || myChar > 3

You are also missing a do at the beginning of the do-while.

Upvotes: 1

nomis
nomis

Reputation: 2715

You are missing a do keyword in your loop. Also your conditional should be reversed:

public static void main(String[] argh) {
    int myChar;
    Scanner in = new Scanner(System.in);
    do {
        System.out.print("choose a player: ");
        myChar = in.nextInt();
    } while (myChar <= 0 || myChar >= 4);

    System.out.println("--------");
    System.out.println("you chose " + myChar);

}

Upvotes: 3

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