Source of PrintBackwardThenForward.java


  1: //PrintBackwardThenForward.java
  2: //Prints the digits of an integer backward, then forward.

  4: public class PrintBackwardThenForward
  5: {
  6:     public static void main(String[] args)
  7:     {
  8:         System.out.println("\nThis program prints the digits "
  9:             + "of a positive integer backward, then forward.\n");

 11:         System.out.print("123 becomes ");
 12:         printBackwardThenForward(123); System.out.println();
 13:         System.out.print("1010 becomes ");
 14:         printBackwardThenForward(1010); System.out.println();
 15:         System.out.print("246810 becomes ");
 16:         printBackwardThenForward(246810); System.out.println();
 17:         System.out.print("7 becomes ");
 18:         printBackwardThenForward(7); System.out.println();
 19:     }

 21:     public static void printBackwardThenForward(int n)
 22:     /**
 23:     Print the digits of an integer backward, then forward.
 24:     @param n The integer whose digits are to be printed
 25:     backward, then forward.
 26:     <p>Pre:<p>n has been initialized with a positive integer.
 27:     <p>Post:<p>The digits of n have been printed backward and then forward.
 28:     */
 29:     {
 30:         if (n < 10)
 31:         {
 32:             System.out.print(n);
 33:             System.out.print(n);
 34:         }
 35:         else
 36:         {
 37:             System.out.print(n % 10);
 38:             printBackwardThenForward(n / 10);
 39:             System.out.print(n % 10);
 40:         }
 41:     }
 42: }