/*
 **************************************************************************
 * Program name : 052_String_in_reverse_order(pointer) (Version 1.00)     *
 * Author       : Duck Wong                                               *
 * Language     : C / C++                                                 *
 * Compiler     : Boodshed Dec-C++ compiler Ver 3.95                      *
 * Computer     : PII350                                                  *
 * O/S          : Windows 98                                              *
 **************************************************************************
 * Version 1.00 : 2000/07/06 - first version                              *
 **************************************************************************
 * Description  : (a) Introduction                                        *
 *                (b) Asking the user to input a string                   *
 *                (c) Print the string forward and backward               *
 *                (d) Try again ?                                         *
 **************************************************************************
*/
#include <iostream.h>
#include <stdlib.h>
#include <iomanip.h>
#include <ctype.h>

int main()
{
 // part 1 : declaration
 const int Size = 31;
 char  InputString[Size];
 char  *p;
 int   Index, Length;
 char  Again;

 // part 2 : Introduction
 cout << "\n\n\t\tString_in_reverse_order (Version 1.00)\n"
      << "\n\tPlease input a string (without space and less than 30 characters"
      << "\n\tlong), then this program will print that string backword.";

 do {
     // part 3 : Asking the user to input a string
     cout << "\n\n\tYour string is           : ";
     cin  >> InputString;
     cout << "\t----------------------------------------------------";

     // part 4 : Ouput result
     p = InputString;                                                 // Note(1)
     cout << "\n\tDisplay in reverse order : ";                       // Note(2)
     for (Index=strlen(p)-1; Index>-1; Index--) cout << p[Index];
     cout << "\n\tConverted to upper case  : ";                       // Note(3)
     for (Index=0; Index<=strlen(p)-1; Index++) cout << char(toupper(p[Index]));
     cout << "\n\tConverted to lower case  : ";                       // Note(3)
     for (Index=0; Index<=strlen(p)-1; Index++) cout << char(tolower(p[Index]));

     // part 5 : try another number ?
     cout << "\n\n\t\aTry another number (Y/N) : ";
     cin  >> Again;
     cout << "\n";
    } while (Again=='Y' || Again=='y');
 cout << "\n" << endl;

 system("PAUSE");
 return 0;
}

/* Note
   (1) The pointer p has been set to the address of the first element in the
       array InputString.

   (2) There are four different ways to get the value in an array :
       Arrayname[Element offset]    e.g.  InputString[3]
       *(Arrayname+offset)          e.g.  *(InputString+3)
       Pointername[Element offset]  e.g.  p[3]
       *(Pointername+offset)        e.g.  *(p+3)

   (3) (a) The functions toupper and tolower (needs the statement #include
           ctype.h) returns an integer value of the character after converting
           to uppercase or lowercase letter.

           Example :
             tolower('A') = 97  , char(97) = 'a'
             toupper('a') = 65  , char(65) = 'A'

       (b) Sample output :

           Your string is           : PeterWong
           ------------------------------------
           Display in reverse order : gnoWreteP
           Converted to upper case  : PETERWONG
           Converted to lower case  : peterwong
*/