#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>

void display_menu( void )
{
        printf( "Type in the appropriate number and press enter\n"
                "1 Converting numbers to binary\n"
                "2 Perform the quincy SHNORKS operation\n"
                "3 sort 6 names\n"
                "4 quit\n\n" );
}

void num_to_bin( void )
{
        printf( "the binary program\n" );
}

void quincy_SHNORKS( void )
{
        printf( "the quincy SHNORKS program\n" );
}

void sort_names( void )
{
        printf( "the sorting program\n" );
}

void quit( void )
{
        exit( 1 );
}

void unknown( char c )
{
        if ( isprint( c ) )
                fprintf( stderr, "Unknown menu choice \"%c\"\n", c );
        else
                fprintf( stderr,
              "Unknown menu choice: character with ASCII value \"%d\"\n", c );

}

int menu( void )
{
        char choice;
        while ( 1 ) {
                display_menu();
                scanf( " %c ", &choice );
                switch ( choice ) {
                        case '1':
                                num_to_bin();
                                break;
                        case '2':
                                quincy_SHNORKS();
                                break;
                        case '3':
                                sort_names();
                                break;
                        case '4':
                        case 'q':
                        case 'Q':
                                quit();
                                break;
                        default:
                                unknown( choice );
                                break;
                }
        }
}

int main( void )
{
        menu();
        return 0;
}