Whats wrong with my looping?

Code java:

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import java.io.*;
   public class dowhile
   {
      public static void main(String[] args)
      {
 
       int START = 0;
       int END = 0;
       int STEP = 0;
       String input = "";
       char a = 'y';
 
               BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
 
 
 
 
  do{     
 
   try{
         System.out.print("Input Starting number: ");
         input = in.readLine();
         START = Integer.parseInt(input);
 
         System.out.print("Input Ending number: ");
         input = in.readLine();
         END = Integer.parseInt(input);
 
         System.out.print("Input Step (interval): ");
         input = in.readLine();
         STEP = Integer.parseInt(input);
      }catch(IOException e)
       {System.out.println("Error");}
 
 
    if( START >= END )
    System.out.println("Starting Should be lesser than the ending number");
 
    if( STEP < 1 )
    System.out.println("Step should be greater than 0");
 
     do{
      System.out.println( START );
 
       START = START + STEP;
 
     }while( START < END && STEP > 0);
 
     try{
     System.out.print("Try again? Y/N: ");
     input = in.readLine();
     a = input.charAt(0); }
     catch(IOException e)
    {System.out.println("Error");}
 
     if(a != 'y' || a != 'Y' || a != 'n' || a != 'N'){
     do{ System.out.println("Enter Y or N only");  
     try{
     System.out.print("Try again? Y/N: ");
     input = in.readLine();
     a = input.charAt(0); }
     catch(IOException e)
    {System.out.println("Error");}
     }while(a != 'y' || a != 'Y' || a != 'n' || a != 'N');}
 
 
 
 
    }while(a == 'y' || a == 'Y');
 
 
}
}

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Its been driving me carzy help pls :mad:

What are the expected outputs, and what outputs are you actually getting?

Check your logic in evaluating the yes/no entries: they will always evaluate to true regardless of the entry and result in an infinite loop.

An easy way to see what the results of a large condition like you are using is to print it:
System.out.println("cond=" + (a != 'y' || a != 'Y' || a != 'n' || a != 'N'));

Put the above just before the while() statement.

Then you can work with your input and the way the above condition is coded to get the desired result.

Quote:

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Originally Posted by helloworld922

What are the expected outputs, and what outputs are you actually getting?

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The code is supposed to input a start an end and an interval which the program does fine... the problem is in the if(a != 'y' || a != 'Y' || a != 'n' || a != 'N') it enters the body even IF character a is equal to one of the four variables

What do you see when you add this print statement to the code just before the while() test?
System.out.println("cond=" + (a != 'y' || a != 'Y' || a != 'n' || a != 'N') + " for a=" + a);

Quote:

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Originally Posted by Norm

What do you see when you add this print statement to the code just before the while() test?
System.out.println("cond=" + (a != 'y' || a != 'Y' || a != 'n' || a != 'N') + " for a=" + a);

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that helped ty \m/