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
  9:         (
 10:             "\nThis program prints the digits "
 11:             + "of a positive integer backward, then forward.\n"
 12:         );

 14:         System.out.print("123 becomes ");
 15:         printBackwardThenForward(123);
 16:         System.out.println();
 17:         System.out.print("1010 becomes ");
 18:         printBackwardThenForward(1010);
 19:         System.out.println();
 20:         System.out.print("246810 becomes ");
 21:         printBackwardThenForward(246810);
 22:         System.out.println();
 23:         System.out.print("7 becomes ");
 24:         printBackwardThenForward(7);
 25:         System.out.println();
 26:     }

 28:     public static void printBackwardThenForward(int n)
 29:     /**
 30:         Print the digits of an integer backward, then forward.
 31:         @param n The integer whose digits are to be printed
 32:         backward, then forward.
 33:         <p>Pre:<p>n has been initialized with a positive integer.
 34:         <p>Post:<p>The digits of n have been printed backward and then forward.
 35:     */
 36:     {
 37:         if (n < 10)
 38:         {
 39:             System.out.print(n);
 40:             System.out.print(n);
 41:         }
 42:         else
 43:         {
 44:             System.out.print(n % 10);
 45:             printBackwardThenForward(n / 10);
 46:             System.out.print(n % 10);
 47:         }
 48:     }
 49: }