Java: Infinite loop using Scanner in.hasNextInt()

Question

I am using the following code: ``` while (invalidInput) { // ask the user to specify a number to update the times by System.out.print("Specify an integer between 0 and 5: "); if (in.hasNextInt()) { // get the update value updateValue = in.nextInt(); // check to see if it was within range if (updateValue >= 0 && updateValue <= 5) { invalidInput = false; } else { System.out.println("You have not entered a number between 0 and 5. Try again."); } } else { System.out.println("You have entered an invalid input. Try again."); } } ``` However, if I enter a 'w' it will tell me "You have entered invalid input. Try Again." and then it will go into an infinite loop showing the text "Specify an integer between 0 and 5: You have entered an invalid input. Try again." Why is this happening? Isn't the program supposed to wait for the user to input and press enter each time it reaches the statement: ``` if (in.hasNextInt()) ```

Accepted Answer

In your last `else` block, you need to clear the 'w' or other invalid input from the Scanner. You can do this by calling `next()` on the Scanner and ignoring its return value to throw away that invalid input, as follows:

```
else
{
      System.out.println("You have entered an invalid input. Try again.");
      in.next();
}
```

Java: Infinite loop using Scanner in.hasNextInt()

Solution

Problem