Java - Switch Statement

import java.io.*;

class ssvswitch
 {
   public static void main(String arg[]) throws IOException
    {
      String t,t1;
      double allo=0;
      int inc,cat;
      double all;


      DataInputStream dr = new DataInputStream(System.in);

      System.out.print("Enter the Income : ");
      t = dr.readLine();
      inc = Integer.parseInt(t);

      System.out.print("Enter the Category : ");
      t1 = dr.readLine();
      cat = Integer.parseInt(t1);

      switch(cat)
       {
         case 1 : allo = 0.05;
                  break;

         case 2 : allo = 0.07;
                  break;

         case 3 : allo = 0.10;
                  break;
       }

         all = inc * allo;
         System.out.println("\nAllowance to be paid : " + all);
   }
 }