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Thread: Nested loop if statement help

  1. #1
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    Default Nested loop if statement help

    Right now my code is generating half of what it is supposed to.

    Program asks the user to enter a number from 1 to 10.

    Enter 7

    output will be $$$$$$$

    I'm having issues with my if statement. Once you put in the wrong number it should ask for another number and so on.

    If statement:
    if( num < 1 || num > 10)
    {
         System.out.print("The number you entered is invalid");
    }

    public static void main(String [] args)
        {
     
            Scanner keyboard = new Scanner(System.in);
     
            int num;
            int num_of_rows = 1;
     
            System.out.print("Enter a number from 1 to 10: ");
            num = keyboard.nextInt();
     
            for (int row = 1; row <= num_of_rows; row++)
            {
                for ( int column = 1; column <= num; column++)
                {
                    System.out.print("$");               
                }     
            }  
            System.out.println();
            System.exit(0);
        }


  2. #2
    Crazy Cat Lady KevinWorkman's Avatar
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    Default Re: Nested loop if statement help

    So you want to ask for different input *while* their input is invalid, right?
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    Default Re: Nested loop if statement help

    Yes, that is correct.

    So, a while loop would be the thing to use?

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    Default Re: Nested loop if statement help

    Quote Originally Posted by CSUTD View Post
    Yes, that is correct.

    So, a while loop would be the thing to use?
    What happened when you tried it?
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    Default Re: Nested loop if statement help

    Not working, I may have done it wrong.

    I enter 2 it prints out "$$" and the "The number you entered is invalid". Even if I enter 20 it says the same thing. But it doesn't ask for the user to enter another number.

    My while loop
    while(num < 1 || num > 10)
    {
        // nested loop in here
        System.out.println("\nThe number you entered is invalid");
    }

  6. #6
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    Default Re: Nested loop if statement help

    Without an SSCCE I can only guess at what your code is doing. But in that while loop, I don't see a place where you're asking for user input.
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    Default Re: Nested loop if statement help

    Quote Originally Posted by KevinWorkman View Post
    Without an SSCCE I can only guess at what your code is doing. But in that while loop, I don't see a place where you're asking for user input.
    public static void main(String [] args)
        {
            Scanner keyboard = new Scanner(System.in);
     
            int num = 0;
            int num_of_rows = 1;
     
            while(num < 1 || num > 10)
            {
                System.out.print("Enter a number from 1 to 10: ");
                num = keyboard.nextInt();
     
                for (int row = 1; row <= num_of_rows; row++)
                {
                    for ( int column = 1; column <= num; column++)
                    {
                        System.out.print("$");               
                    } 
                }
               System.out.println("\nThe number you entered is invalid");
            }
     
            System.out.println();
            System.exit(0);
        }

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    Default Re: Nested loop if statement help

    I'm really not sure what you expect the program to do- look through it line by line, and it should become pretty clear what's going on.

    You're asking for a number, and regardless of its value you're printing out "$" a certain number of times. Then, regardless of its value, you're telling them the number is invalid. Then, if the number is indeed valid, you're repeating the process.
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