CODEWITHSUNDEEP
javaexceptionjava.util.scanner
Benjamin Lowry
Benjamin Lowry

Reputation: 3789

Scanner skipping over user input

I am trying to do a chess game and at a certain point the user inputs a number relating to what piece they want to move. I had a simplified version of the code below earlier, but I recently decided to put a 'try' and 'catch' statement to catch the InputMismatchException. This is the code:

int inputexception = 0;

do {

    inputexception = 0;

    try {

        System.out.println("What piece would you like to move?");           
        pieceselectioninput = scan.nextInt();

    } catch ( InputMismatchException e ){

        inputexception = 1;

    }

} while ( inputexception == 1 );

So once I run this program, if I input a non-Int value, it repeats on and on forever with "What piece would you like to move?" being displayed on the screen continuously until I manually terminate the program.

What am I doing wrong? It wasn't like this until I added the 'try' and 'catch' phrases.

Upvotes: 0

Views: 102

Answers (2)

SomeJavaGuy
SomeJavaGuy

Reputation: 7347

There are two solutions to your problem:

keep nextInt

int inputexception = 0;

do {
   inputexception = 0;

   try {

       System.out.println("What piece would you like to move?");           
       pieceselectioninput = scan.nextInt();

    } catch ( InputMismatchException e ){
        // Get the next line so it won´t repeat forever
        scan.nextLine();
        inputexception = 1;
    }
} while ( inputexception == 1 );

Directly use the nextline Statement with parsing:

int inputexception = 0;

do {

inputexception = 0;

    try {

        System.out.println("What piece would you like to move?");     
        String input = scan.nextLine();
        pieceselectioninput = Integer.parseInt(input);

    } catch ( NumberFormatException e ){
        inputexception = 1;
    }
} while ( inputexception == 1 );

Upvotes: 0

ghdalum
ghdalum

Reputation: 891

You run the while-loop as long as inputexception == 1, and you set the inpuexception value to 1 in the catch block of the InputMismatchException. This makes the loop continue every time you type a non int value.

Upvotes: 1

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