Input (Scanner) variable in while loop

Question

Im trying to make the program to ask for a percentage (grade) but I want it to ask again after the user has made the first input and has seen the output. I'm having trouble with the loop because the variable myMark is no assigned.

import java.util.Scanner;
public class passFail{


    public static void main(String[] args){

        Scanner result = new Scanner(System.in);
        int myMark = 0;

        while(myMark >=0 && myMark <=100){

            System.out.println("Please enter the percentage you have received:");
            myMark = result.nextInt();

            if(myMark <=49 && myMark >=0){

                System.out.println("You have failed!");
            }

            else if(myMark <=59 && myMark >=50){
                System.out.println("You have passed!");
            }

            else if(myMark <=69 && myMark >=60){
                System.out.println("You have received a Credit");
            }

            else if(myMark <=79 && myMark >=70){
                System.out.println("You have received a Distinction!");
            }

            else if(myMark <=100 && myMark >=80){
                System.out.println("You have received a High Distinction");
            }

            else{
                System.out.println("Please enter a whole number");
            }


        }

    }


}

possible duplicate of Stop scanner from reading user input java? — Rohit Jain
– Rohit Jain, Commented Oct 8, 2012 at 5:04

kosa · Accepted Answer · 2012-10-08 05:00:41Z

2

You need to define myMark first before using it. Something like below:

  Scanner result = new Scanner(System.in); 
  int myMark = result.nextInt();

  while(myMark >=0 && myMark <= 100){

        System.out.println("Please enter the percentage you have received:");
        myMark = result.nextInt();
      ..................

answered Oct 8, 2012 at 5:00

kosa

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3 Comments

Code-Apprentice Over a year ago

I'll also point out that you only need to create the Scanner once before the loop starts. You don't need to create it each time inside the loop.

Kronos Over a year ago

This did not work. I have updated my question with the working code.

kosa Over a year ago

@Kronos: Instead of updating question, it would be clear for future users if you can post it as answer and accept it.

Rohit Jain · Accepted Answer · 2012-10-08 05:08:06Z

1

You should declare your myMark before using it in while loop condition.. Also, you should declare your Scanner as instance variable..

public class Demo {
    private Scanner scanner = new Scanner(System.in);

    public static void main(String[] args) {

        int myMarks = 0;
        while (myMarks >= 0 && myMark < 100) {
            // Rest is all same
        }
    }
}

answered Oct 8, 2012 at 5:08

Rohit Jain

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Comments

Kumar Vivek Mitra · Accepted Answer · 2012-10-08 05:03:25Z

1

- You have forgotten to declare the variable myMark.

- You have declare it to a Type (Data Type)

Eg:

int myMark;

- And it would be nicer if you place the Scanner outside the loop, cause you want to get the input only once...

answered Oct 8, 2012 at 5:03

Kumar Vivek Mitra

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