Switch statement not working...

[dwlniles]

// This is the error message I'm getting..C:\Program Files\Java\jdk1.6.0_25\bin>javac c:\java\Grade1.java
// c:\java\Grade1.java:49: variable grades might not have been initialized
//               switch(grades)
//                      ^

import java.util.Scanner;
   import java.text.*;
   import javax.swing.*;
   import java.util.*;
   import java.io.*;   

   public class Grade1
   {   
      public static void main (String[] args)    
      {

         String str, lgrade, studentName, courseName;
         int studentNo, totalsum, noCourse, c;
         char grades;     
         double gp = 0.0;
         double totalgp = 0.0;
         double gpa = 0.0;
         double n = 0.0;

         studentName = JOptionPane.showInputDialog(null,"Enter Student Name");

         str = JOptionPane.showInputDialog(null,"Enter Student Number:");    
         studentNo = Integer.parseInt(str);

         str = JOptionPane.showInputDialog(null,"Enter Number of Courses:");
         noCourse = Integer.parseInt(str);

         //try statement

         try

         {

             //set up buffered output filestream

            FileWriter fw = new FileWriter("grades.txt");
            BufferedWriter bw = new BufferedWriter(fw);
            PrintWriter pw = new PrintWriter(bw);
            pw.println("ABC College Report For"); 
            pw.println(studentName);
            pw.println(studentNo);
            pw.println("\n");
            pw.println("\nCourse" + "     " + "Letter Grade" + "     " + "Gradepoints");
            for(c = 0; c < noCourse; ++c)
{
               courseName = JOptionPane.showInputDialog(null, "Enter Course Name & Section:");    
               lgrade = JOptionPane.showInputDialog(null, "Enter Grade:");           

               switch(grades)
               {
                  case 'A': gp=4; 
                     break;
                  case 'B': gp=3; 
                     break;
                  case 'C': gp=2; 
                     break;
                  case 'D': gp=1; 
                     break;
                  default: gp=0;               
               }
               totalgp+=gp;
            pw.println(courseName + "          " + lgrade + "      " + gp); 
}

               gpa = (totalgp / n);
               pw.println("GPA: " + gpa);
               pw.close(); //close file 
          }
            //catch statement            
            catch(IOException e)

            {               
               System.out.println("Error: " + e.getMessage());               
            }

            // finally statement            
         finally            
         {            
            System.exit(0);            
         } 
      }
   }

[zeroliken]

the variable grades has no value thus the error states that it hasn't been initialized