#include <stdio.h>
#include <conio.h>

#define CR 0x0d   //carriage return
#define ESC 0x1b  //Escape key
#define TAB 0x09
#define LF 0x0a   //line feed
#define BACKSPACE 0x08
#define NULL 0    //Empty character
#define TRUE 1
#define FALSE 0
#define LENGTH 15 //size of the string

int input(char *string, int length);

void main()
{
    char string[LENGTH];

    printf("What is your name?");
    if(!input(string,LENGTH))
         printf("Darn glad to meet you, %s!\n",string);
    else
         printf("\n*** Canceled");
}

int input(char *string, int length)
{
    int done = FALSE;
    int cancel = FALSE;
    int index = 0;
    char ch;

    string[0] = NULL; //init the buffer

    do
    {
        ch = getch();

  /* Check to see whether the buffer is full */

        if (index == length)
        {
            switch(ch)
            {
                case ESC:
                     done = TRUE;
                     cancel = TRUE;
                     break;
                case CR:
                     break;
                case BACKSPACE:
                     break;
                default:
                    ch = NULL;
                    break;
            }
        }

        /* Process the keyboard input */

        switch(ch)
        {
         case ESC:  //Escape key
              done = TRUE;
              cancel = TRUE;
              break;
         case CR:   //Enter key
              putchar(ch);
              putchar(LF);
              string[index] = NULL;
              done = TRUE;
              break;
         case BACKSPACE:
              if(index==0)
              {
                break;
              }
              else
              {
                putchar(ch);
                putchar(' ');
                putchar(ch);
                index--;
                break;
              }
         case NULL:
              break;
         default:   //display & store
              putchar(ch);
              index[string] = ch;
              index++;
              break;
        }
    }
    while(!done);
    return(cancel);
}