Why is my While Loop wont loop my Catch, like my if else statement?-CodePudding

I am trying to make a program where the user will input a random integer/number. But the main issue is, if user accidentally input a String, I want them to be informed and also I want them to ask to input again by asking them again. But in my code I cant loop my catch.

public static void main(String[] args) {

        Scanner scan = new Scanner(System.in);

        int answer = 28;
        int attempts = 0;
        
        System.out.println("Guess a Number 1 - 50:");
        
        
        while(true) {
            try {
                int input = scan.nextInt();
                scan.nextLine();
                if(input > answer) {
                    System.out.println("Too Big");
                    System.out.println("Guess a Number 1 - 50:");
                } else if (input < answer) {
                    System.out.println("Too Small");
                    System.out.println("Guess a Number 1 - 50:");
                } else if (input == answer ) {
                    System.out.println("Congrats!");
                } 
            } catch (InputMismatchException e) {
                System.out.println("Numbers only");
                System.out.println("Guess a Number 1 - 50:");
                
            } 
            
            
        }

}
}

CodePudding user response：

Try-catch block stops the execution of the while loop when it throws an error (when you had a catch). You can use another if-else statement to check if it was a number instead of a try-catch block.

public static boolean isNumeric(String string) {
    int intValue;
        
    System.out.println(String.format("Parsing string: \"%s\"", string));
        
    if(string == null || string.equals("")) {
        System.out.println("String cannot be parsed, it is null or empty.");
        return false;
    }
    
    try {
        intValue = Integer.parseInt(string);
        return true;
    } catch (NumberFormatException e) {
        System.out.println("Input String cannot be parsed to Integer.");
    }
    return false;
}

you can use a helper method like this to return true or false in your if statement.

check this URL for more information.

ps : This is only one method of implementation. I think you will be able to work around with some solution with try-catch also. You can try implementing inputting user input again inside the catch block to repeat the process.

CodePudding user response：

You should try this code, It will work perfectly for your requirement...


    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int answer = 28;
        int attempts = 0;
        System.out.println("Guess a Number 1 - 50:");

        boolean condition = true;

        while (condition) {
            try {
                boolean condition2=true;
                while (condition2) {
                    int input = scan.nextInt();
                    scan.nextLine();
                    if (input > answer) {
                        System.out.println("Too Big");
                        System.out.println("Guess a Number 1 - 50:");
                    } else if (input < answer) {
                        System.out.println("Too Small");
                        System.out.println("Guess a Number 1 - 50:");
                    } else {
                        System.out.println("Congrats!");
                        condition2=false;
                    }
                }
                condition = false;
            } catch (InputMismatchException e) {
                System.out.println("Numbers only");
                System.out.println("Guess a Number 1 - 50:");

            }


        }
    }