Reading and writing of alphabets in reverse case

Program 12) A program that reads a character from keyboard and then prints it in reverse case. That is, if the input is upper case,the output will be lower case.

The program uses three functions: islower, toupper, tolower. The function islower is a conditional function and takes the value TRUE if the argument is a lowercase alphabet; otherwise takes the value FALSE. The function toupper converts the lowercase arguement into an uppercase alphabet while the function tolower does the reverse.

                                     PROGRAM

#include <stdio.h>
#include <ctype.h>
main( )
 {
        char alphabet ;
        printf("Enter an alphabet") ;
        putchar('\n') ;    /* move to next line */
        alphabet = getchar( ) ;
        if(islower(alphabet) ) 
             putchar(toupper(alphabet) ) ;
        else
             putchar(tolower(alphabet) ) ;
        getch( ) ;
 }


Output:                  Enter an alphabet
                              a
                              A
                              Enter an alphabet
                              Q
                              q
                              Enter an alphabet
                              z
                              Z