How to get a number entered by the user to exit a loop?

Question

I'm trying to get the user to input any number between 0 and 10 an unlimited amount of times until they want to stop. They stop by entering the value -1. So far i have been able to create what happens when they enter a correct value, but when they enter -1 (which is an invalid value in the while loop), the program knows that it's invalid. All I'm looking for is for the program to exclude -1 for the possible invalid input, and to make the program stop asking for more input. Here's my code so far:

    int userInput=0;
    System.out.println("Please enter numbers ranging from 0 to 10 (all inclusive).");
    System.out.println("When you want to stop, type and enter -1.");


    while (userInput <= 10 && userInput >= 0)
    {
        userInput=Integer.parseInt(br.readLine());

        while (userInput > 10|| userInput < 0)
        {
            System.out.println("That number is not in between 0 and 10. Please enter a correct number.");
            userInput=Integer.parseInt(br.readLine());
        }
        sum=sum+userInput;
        freq++;
    }
    while (userInput == -1)
    {
        System.out.println("You have chosen to stop inputing numbers.");
    }

Sorry for my limited understanding :/

Answer 1

I would suggest that you're trying to do too much with while loops. As it's written, you never get out of your first one. If you enter a number between 0 and 10, it goes back and asks again. If you put anything other than that, you hit that nested while loop and it ends up asking for a number again. Think about the flow and what you want it to do. Here's a quick outline of one way to go at it:

System.out.println("Please enter numbers ranging from 0 to 10 (all inclusive).");
System.out.println("When you want to stop, type and enter -1.");
keepgoing = true;
while(keepgoing) {
    userInput=Integer.parseInt(br.readLine());
    if((userInput <= 10 && userInput >= 0) {
        sum=sum+userInput;
        freq++;
    }
    else if(userInput == -1) {
        System.out.println("You have chosen to stop inputing numbers.");
        keepgoing = false;
    }
    else {
        System.out.println("That number is not in between 0 and 10. Please enter a correct number.");
    }
}

At least I think it gets there. There are various methods to control the flow of your code. It's good to know when to use which one.