Ytukyg

I am trying to ask the user to input a number from 0-9. If they input the right number, the program terminates, but if they do not, they have three chances to get the right number until they are asked to re-run the program again.

This is my code so far:

import java.util.Scanner;



public class DoWhileLoop

{

    public static void main(String args)

    {

        int a = 1;

        Scanner keyboard = new Scanner(System.in);





        do{

            a++;

            System.out.println("Please enter a number 0-9");

            int value = keyboard.nextInt();





            if(value == 1)

            {

                System.out.println("one");

            }

            else if(value == 2)

            {

                System.out.println("two");

            }

            else if(value == 3)

            {

                System.out.println("three");

            }

            else if(value == 4)

            {

                System.out.println("four");

            }

            else if(value == 5)

            {

                System.out.println("five");

            }

            else if(value == 6)

            {

                System.out.println("six");

            }

            else if(value == 7)

            {

                System.out.println("seven");

            }

            else if(value == 8)

            {

                System.out.println("eight");

            }

            else if(value == 9)

            {

                System.out.println("nine");

            }

            if (value <= 9) {

                break;

            }

        }while (a <= 3);

            System.out.println("Please rerun the program and enter a number 0-9");

    }

}

if you have any advice on what to do, it would be greatly appreciated.

you can have your code like this instead:

public class DoWhileLoop {

        public static void main(String args) {

            Scanner in = new Scanner(System.in);

            Random rand = new Random();

            int num = rand.nextInt(10);

            Boolean correct = false;

            int attempts = 0;

            do{

                if (attempts == 3) {

                    System.out.println("rerun the program");

                    break;



                }

                System.out.println("Enter number 1-9");

                int ans = in.nextInt();

                if (ans == num) {

                    correct = true;

                    System.out.println("Correct! the number is: " + ans);

                } else {

                    attempts++;

                }

            }while(!correct); 

        }

    }

here is a some reading for you : https://docs.oracle.com/javase/tutorial/java/javaOO/returnvalue.html

the return statement is used to return a value from a method.

for example if you want to create the class number which is able to divide two number it you can return the resultat of your function and using it like in a System.out.println for example.

public class Number

{



public static void main(String args)

{

    System.out.println(divide(4, 5));

    System.out.println(divide(4,0));





}



    public static float divide(int a, int b)

    {

        if(b == 0) {

          throw new IllegalArgumentException("Error you can't divide by zero !");

        }

        return a / b;



  }



}

For the throw it's a little more complicated, in java it can happens you have exception for example you can't divide by 0. In this case throw an exception in this case an IllegalargumentException.

Finally your method main is well named because this is the main method of your programm, the first one to be executed and if the programm had no error the last one which means if you leave this method you will leave your programm.

You have to move your "a++" into the else statement in the end of the code. Something like this:

import java.util.Scanner;



public class DoWhileLoop {

public static void main(String args) {

    int a = 0;

    Scanner keyboard = new Scanner(System.in);

    do{

        System.out.println("Please enter a number 0-9");

        int value = keyboard.nextInt();



        if(value == 1){System.out.println("one");}

        else if(value == 2) {System.out.println("two");}

        else if(value == 3) {System.out.println("three");}

        else if(value == 4){System.out.println("four");}

        else if(value == 5){System.out.println("five");}

        else if(value == 6){System.out.println("six");}

        else if(value == 7){System.out.println("seven");}

        else if(value == 8){System.out.println("eight");}

        else if(value == 9){System.out.println("nine");}

        if (value <= 9) {break;}

        else {a++;}

        }

    while (a < 3);

    if (a == 3) {System.out.println("You've used all your attemps.");}        

}

}

Your attempt looks very close to what you want to achieve.

You currently have the following piece of code which will cause the program to terminate if a user enters any number less than or equal to 9

if (value <= 9) {

            break;

        }

In order to strictly meet the requirement that the program terminates if the user enters a number from 0-9 perhaps this check should be something more like:

if (value >=0 && value <=9) {

            break;

}

In java, you can use the && operator within an if statement to ensure that the code inside the if statement only executes if both of the conditions on either side of the && are true.

Why not also add a print statement which prompts the user that they have entered a correct answer? For example

if (value >=0 && value <=9) {

            System.out.println("Correct");

            break;

}

In terms of your current code, it already exits if a user enters any number greater than 9 more than 3 times, so that is good. I think if you fix the if statement I've mentioned above then you should be closer to the behaviour you expect.

The last thing to note is that the program will call this line

            System.out.println("Please rerun the program and enter a number 0-9");

Regardless of how the do-while loop exits. If you want the program to completely terminate when a user enters a correct guess, without printing this line, you can just add a return statement instead of a break:

    if (value >=0 && value <=9) {

            System.out.println("Correct");

            return;

}

This will cause the main method to 'return' rather than continuing to execute any more instructions, this will cause the program to terminate