Scanner user input not working in conjunction with while loop.

[TheNadz]

I'm sure I'm doing something completely idiotic but this is stumping me. I'm having the same issue with another program and have no clue where to go from here.

Scanner s = new Scanner(System.in);
System.out.print(string1);
while(s.nextInt() < 10)
System.out.print(string2);
int n = s.nextInt();

When I comment out the while loop it works perfectly. With the while loop active, if I enter a number that shouldn't activate it, string2 is not printed but I'm given a second Scanner input box that shouldn't be there. If I do trigger the while loop, it prints string2 but then the same problem - it gives me a second, unnecessary Scanner input box.

Can anyone help me? Please!

Thanks!
-Nadz

[Fubarable]

What is the purpose of this code? Can you show a small compilable program that demonstrates your problem? It preferably will have a small main method and nothing else.

edit: and what do you mean by "scanner input box"?

[TheNadz]

Can do. Give me a second to get one together.

EDIT: Here you go:

import java.util.*;

public class test
{
  
  public static void main(String[] args)
  {
    
    Scanner s = new Scanner(System.in);
    
    System.out.print("What n would you like to go up to?");
    while(s.nextInt() < 10)
      System.out.print("How about we try a bigger number, eh?");
    int n = s.nextInt();
    
    System.out.print(n);
    
  }
  
}

[Fubarable]

I would use a do-while loop since you have to run the loop at least once. Also, you must take care not to discard a desirable result as you do in your code above. If the user enters a number > 10, you get the number here:

while(s.nextInt() < 10)

but you don't save it. That's why the user is forced to enter another number.

e.g.,

      Scanner s = new Scanner(System.in);
      int testInt = 0; 
      do {
         System.out.print("Enter an number greater than 9: ");
         testInt = s.nextInt();
      } while (testInt < 10);
      System.out.println("you entered: " + testInt);

Also, you will want to enclose your while loop or do-while loop (or any loop or block) in curly braces. It may not seem important, but it will prevent some dumb mistakes (speaking from experience).

[TheNadz]

Thanks! I'll give that a go.

And yeah, I tend to be lazy with the one line loops but it would be wise to use the brackets.

-Nadz

[Fubarable]

Thanks! I'll give that a go.

Great. Please let us know how it works out.

And yeah, I tend to be lazy with the one line loops but it would be wise to use the brackets.

and I used to be the same way, but no more. I find that using curly braces always makes for less work later, and so is a smarter way to be lazy.