#include <stdio.h>                                                        
#include <bios.h>                                                         
#include <ctype.h>                                                        
                                                                          
#define RIGHT  0x01                                                       
#define LEFT   0x02                                                       
#define CTRL   0x04                                                       
#define ALT    0x08                                                       
                                                                          
int main(void)                                                            
{                                                                         
   int key, modifiers;                                                    
                                                                          
   /* function 1 returns 0 until a key is pressed */                      
   while (bioskey( 1 ) ==  0 );                                               
                                                                          
   /* function 0 returns the key that is waiting */                       
   key = bioskey( 0 );                                                      
                                                                          
   /* use function 2 to determine if shift keys were used */              
   modifiers = bioskey( 2 );                                                
   if (modifiers)                                                         
   {                                                                      
      printf("[");                                                        
      if (modifiers & RIGHT) printf("RIGHT");                             
      if (modifiers & LEFT)  printf("LEFT");                              
      if (modifiers & CTRL)  printf("CTRL");                              
      if (modifiers & ALT)   printf("ALT");                               
      printf("]");                                                        
   }                                                                      
   /* print out the character read */                                     
   if (isalnum(key & 0xFF))                                               
      printf("'%c'\n", key);                                              
   else                                                                   
      printf("%#02x\n", key);                                             
   return  0 ;                                                              
}