The given example will display aestricks on hitting any key.

#include "stdio.h"
#include "conio.h"
#include "ctype.h"

int main()
{    
    char data[15]; /* max length 14 characters say */
    int  index = 0;
    int i;
    for(i = 0; i < 15; i++) data[i] = '\0';


    printf("Enter data : ");

    while(index < 14)
    {
        char ch = getch();

        if(ch == 13) 
        {
           break;
        }
        else if (ch == 8) 
        { 
           if (index > 0)
           {
              putchar(8);
              putchar('\0');
              putchar(8);
              index--;
              data[index] = '\0';
           }
        }
        else if (isalnum(ch))
        {
           putchar('*');
           data[index] = ch; 
           index++;
        }
    }

    printf("\nYour data is %s\n\n", data); 

    return 0;
}

it is not that exactly what i want .I want when we ask input user hit any key (defautly hit button is shown in compiler) i want only * to be print