Char type Comparisson

Hello everybody I’m a beginner in java, and I’m having problems trying to compare character in my program.
I’m trying to have the user type a character and in the character it is not a correct one then tell the user to input the character again .

thank in advance here is the code:

Code :

---

import javax.swing.JOptionPane;
public class test
{
      public static void main(String[] args)
      {	
            String strnGrade = JOptionPane.showInputDialog("Enter the Grade for the course ");
            char grad = strnGrade.charAt(0);
            grad = Character.toUpperCase(grad);
            while  (grad != 'A' || grad != 'B' || grad != 'C' || grad != 'D' || grad != 'F')
            {
                   strnGrade = JOptionPane.showInputDialog
                   ("The Garde enter is invalid please enter the grade again");
             }
       }
}

---

Your logic is flawwed... You're asking grad to be 'A', 'B', 'C', 'D', and 'F' at the same time, which it can't.

Switch the exclusive or logic to exclusive and (&&)

thank you now its working fine...wonderful
here the new code

Code :

---

import javax.swing.JOptionPane;
public class test
{
  public static void main(String[] args)
  {	
    String strnGrade = JOptionPane.showInputDialog("Enter the Grade for the course ");
    char grad = strnGrade.charAt(0);
    grad = Character.toUpperCase(grad);
    while  (grad != 'A' && grad != 'B' && grad != 'C' && grad != 'D' && grad != 'F')
    {
      strnGrade = JOptionPane.showInputDialog
      ("The grades for the course are invalid please enter the grade againg");
      grad = strnGrade.charAt(0);
      grad = Character.toUpperCase(grad);
    }
    System.out.println(grad);
  }
}

---

I have marked this thread as solved :)

You can do this yourself in the 'Thread Tools' menu at the top.

thank you:)... i didn't know how to do it but now i know :-bd; and thanks again