#include <graphics.h> 
#include <math.h> 
#include <stdlib.h> 
#include <dos.h> 
#define KEY_ESC 0x01 
#define KEY_SPACE 0x39 
#define KEY_UP 0x48 
#define KEY_LEFT 0x4b 
#define KEY_RIGHT 0x4d 
#define KEY_DOWN 0x50 
int gamespeed=1200;/*自己改游戲的速度*/ 
int speed;/*飛碟移動速度*/ 
int col;/*中心坐標*/ 
int score=0;/*得分*/ 
char key_state[128],key_pressed[128];/*鍵盤操作用的變量*/ 
void Init();/*初始*/ 
void Close();/*關閉*/ 
void PlayGame();/*游戲過程*/ 
void PrScore();/*輸出成績*/ 
void DrawM(int x,int y,int color);/*畫瞄準器*/ 
void Win();/*輸出最后結果*/ 
int GetKey(int ScanCode);/*這里開始都是按鍵函數*/ 
void interrupt far (*OldInt9Handler)(); 
void far interrupt NewInt9(); 
void InstallKeyboard(); 
void ShutDownKeyboard(); 
DrawFly(int x,int y,int color);/*畫飛碟*/ 
void main(void) 
{ 
Init(); 
PlayGame(); 
Close(); 
} 
void PrScore()/*輸出成績*/ 
{ 
char s[10]; 
setfillstyle(SOLID_FILL,BLACK); 
bar(30,0,100,50); 
setcolor(6); 
settextstyle(0,0,2); 
sprintf(s,"%d",score); 
outtextxy(30,20,s); 
} 
void DrawM(int x,int y,int color)/*畫瞄準器*/ 
{ 
setcolor(color); 
rectangle(x-10,y-10,x+10,y+10); 
line(x-8,y,x+8,y); 
line(x,y-8,x,y+8); 
} 
void Win()/*輸出最后結果*/ 
{ 
settextstyle(0,0,4); 
setcolor(RED); 
if(score>18) 
outtextxy(200,200,"VERY GOOD"); 
else if(score>10) 
outtextxy(250,200,"GOOD"); 
else 
outtextxy(250,200,"~@_@~"); 
} 

void PlayGame()/*游戲過程*/ 
{ 
float x,y;/*飛碟的坐標*/ 
int mx,my; 
int i,num=0; 
for(i=40;i<640;i+=30) 
DrawFly(i,65,WHITE); 
mx=my=300; 
setcolor(15); 
line(0,80,640,80); 
randomize(); 
while(num<20) 
{ 
  PrScore();/*輸出成績*/ 
  col=random(10);/*中心坐標隨機*/ 
  col=col*20+200; 
  speed=2+random(2);/*飛碟速度隨機*/ 
  for(x=-250;x<=250;x+=speed)/*飛碟移動全過程*/ 
  { 
   y=pow((x/10),2)+200;/*求y坐標*/ 
   DrawFly(x,y,WHITE); 
   DrawM(mx,my,YELLOW); 
   delay(gamespeed);/*間隔*/ 
   DrawM(mx,my,BLACK); 
   DrawFly(x,y,BLACK); 
  if(GetKey(KEY_ESC))/*結束游戲*/ 
  break; 
  if(GetKey(KEY_LEFT)) 
  mx-=4; 
  if(GetKey(KEY_RIGHT)) 
  mx+=4; 
  if(GetKey(KEY_DOWN)) 
  my+=4; 
  if(GetKey(KEY_UP)&&my>100) 
  my-=4; 
  if(GetKey(KEY_SPACE))/*發子彈*/ 
   { 
    if(((x+col+10)>=(mx-2)&&x<=(mx+2))&&(y>=(my-2)&&y<=(my+2)))/*這里控制精確度*/ 
    { 
    score++; 
    DrawFly(x,y,BLACK); 
    DrawM(mx,my,YELLOW); 
    PrScore(); 
    DrawM(mx,my,BLACK); 
    break; 
    } 
   } 
   if(y>490&&col+x>col)/*自動消失*/ 
   break; 
  } 
  if(y<490) 
  { 
  setcolor(RED); 
  line(40+num*30-10,55,40+num*30+10,75); 
  line(40+num*30-10,75,40+num*30+10,55); 
  } 
  num++; 
  if(GetKey(KEY_ESC))/*結束游戲*/ 
  break; 
} 
Win(); 
while(1) 
{ 
if(GetKey(KEY_ESC)) 
break; 
} 
} 
void Init()/*初始*/ 
{ int gd=DETECT,gm; 
initgraph(&gd,&gm,"c:\\tc"); 
cleardevice(); 
InstallKeyboard(); 
} 
void Close()/*關閉*/ 
{ 
ShutDownKeyboard(); 
closegraph(); 
} 
DrawFly(int x,int y,int color)/*畫飛碟*/ 
{ 
setcolor(BLACK); 
setfillstyle(SOLID_FILL,color); 
fillellipse(col+x,y,10,6); 
} 
void far interrupt NewInt9(void) 
{ 
unsigned char ScanCode,temp; 
ScanCode=inportb(0x60); 
temp=inportb(0x61); 
outportb(0x61,temp | 0x80); 
outportb(0x61,temp & 0x7f); 
if(ScanCode&0x80) 
   { 
    ScanCode&=0x7f; 
    key_state[ScanCode]=0; 
   } 
else 
   { 
    key_state[ScanCode]=1; 
    key_pressed[ScanCode]=1; 
   } 
outportb(0x20,0x20); 
} 

void InstallKeyboard(void) 
{ 
int i; 
for(i=0;i<128;i++) 
key_state[i]=key_pressed[i]=0; 
OldInt9Handler=getvect(9);         /*中斷向量值*/ 
setvect(9,NewInt9);                /*中斷程序NewInt9地址存入指定的中斷向量表中INT 09H*/ 
} 

void ShutDownKeyboard(void) 
{ 
setvect(9,OldInt9Handler); 
} 

int GetKey(int ScanCode) 
{ 
int res; 
res=key_state[ScanCode]|key_pressed[ScanCode]; 
key_pressed[ScanCode]=0; 
return res; 
}