Not breaking out of loop

Question

I've written this piece of code to search through a file until it finds:
          BufferedReader in = new BufferedReader (new FileReader(outputFile));
          String name = null;
          String data = in.readLine();
          while (name == null)
               System.out.print("Please enter your name: ");
               name = kybd.nextLine();
               kybd.nextLine();
               while (data != null)
                    if (name.equalsIgnoreCase(data))
                         name = data;
                    else
                         name = null;
                    data = in.readLine();
               System.out.println("Sorry, name not found.");
               System.out.println();
          }I have some problems with the logic of it and it doesn't break out of the loops, can someone give me some advice as to where it's going wrong and how to correct this, thanks.
I've now discovered that the "kybd.nextLine();" was causing it not to enter the first loop, however now I get a NullPointerException and I know what that is, but I do not know why it is happening here.
Edited by: jnaish on Jul 2, 2008 6:40 AM

Answer 1

jnaish wrote:
Changed it to look like this:
          while (name == null || name == "no match")
Don't do this. You're comparing object identity instead of comparing their values. Compare strings with .equals().
               System.out.print("Please enter your name: ");
               name = kybd.nextLine();
               //kybd.nextLine();
               while (data != null)You never set data (you did in your first example), so data will be null and your loop will not execute.
                    if (name.equalsIgnoreCase(data))
                         name = data;
                         System.out.println("Found.");
                    else
                         name = "no match";
                    data = in.readLine();
               System.out.println("Sorry, name not found.");
               System.out.println();
          }No exception anymore but, name doesn't become equal data either.Restructure your loop. What you're doing is just awkward.
Pseudocode:
function {
  get line of user input
  loop over lines in file {
    if user input is equal to line from file {
      print "found"
}Edited by: nclow on Jul 2, 2008 2:11 PM