函数名: bioskey 
 功  能: 直接使用BIOS服务的键盘接口 
 用  法: #include <bios.h> 
         int bioskey(int cmd); 
 程序例: 
#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; 
 }