while loop problem

Question

I call the triangleInput() method from another class 3 times to get 3 different numbers from the user. the while loop should keep looping until the user enters a valid integer. but it doesn't loop the first time. any ideas how to get round this? w do while worked a bit weird.

//code

Scanner sc = new Scanner(System.in);

public static int triangleInput(){
int insides = 0; // to hold user input to return

while(!sc.hasNextInt()){
System.out.println("Enter a number:") ;
insides = sc.nextInt();
}
return intSides;
}

Answer 1

try to remove !

should be:

while(sc.hasNextInt ())

Answer 2

the problem when I take that out is if the user enters something invalid, it breaks out of the loop and moves on to the next number, meaning it misses a number.

what I'm trying to do in that loop is keep asking the user for a number until he enters a valid one, it then returns that number and the method is called again.

Answer 3

Is the below is what you want:

import java.util.Scanner;

public class Program
{
public static void main(String[] args) {

System.out.println(triangleInput());

}

public static int triangleInput(){
int insides = 0; // to hold user input to return

Scanner sc = new Scanner(System.in);

while(true){
System.out.println("Enter a number:") ;

try{
insides = sc.nextInt();

return insides;
}catch(Exception e){
if (sc != null) sc.next ();
}
}

}
}