为什么我的switch语句不起作用并陷入无限循环？

Question

I'm trying to get it to output the users fortune, but it will only output the number the user entered infinitely.

What am I doing wrong? How can I fix the infinite loop?

public static void main(String[] args) {

    Scanner broncos = new Scanner ( System.in );

    int x, y, a;

    System.out.println("Would you like me to tell your fortune? Type 1 for yes and any other number for no: ");
    x = broncos.nextInt();


    while (x==1)
    {   
        System.out.println("Enter a number from 1-8: ");
        y = broncos.nextInt();

        while ( y > 0 && y < 9)

        System.out.println( y );
        System.out.print ( "That's not a valid number. Try again. ");
        y = broncos.nextInt();
    }


    System.out.println ("Enter a number from 1-8: ");
    a = broncos.nextInt();


    switch (a) 
    {
        case 8 : 
            System.out.println ("You will win the lottery" );
            break; 
        case 7 : 
            System.out.println ("You are going to do great things");
            break; 
        case 6 : 
            System.out.println ("Don't get out of the house today");
            break; 
        case 5 : 
            System.out.println ("You'll get a raise at work");
            break;  

        case 4 : 
            System.out.println ("Lucky day today");
            break; 

        case 3 : 
            System.out.println ("Not so lucky day today");
            break; 

        case 2 : 
            System.out.println ("Your favorite sports team will win" );
            break; 

        case 1 :
            System.out.println ("Your car is going to break down" );
            break;

        default: 
            System.out.println ( "You didn't enter 1-8!" );
    }

    broncos.close();
}

Answer 1

It's not your switch statement that's causing problems but rather the while loop prior. You test x as in while (x==1) , but where do you change x within the while loop? If you never change the state of x , the test will never become false, and the loop will never exit.

As Tom astutely points out, you will want your while loop that validates your y input, to enclose all the code that is related to getting the y input.

while ( y > 0 && y < 9) {
    System.out.println("Enter a number from 1-8: ");
    y = broncos.nextInt();

    if (y > 0 && y < 9) {    
        System.out.println( y );
        System.out.print ( "That's not a valid number. Try again. ");
    }
}

Now use your correct y in your switch statement.

Also, once you have a correct y , there's no need to get an a :

// System.out.println ("Enter a number from 1-8: ");
// a = broncos.nextInt();

Again, just use y in the switch statement.

As for your x , there's no need to validate it (unless you need to check to see that it is infact a number) since any number entered should work.