模拟自由落体下落，弹回程序．

　我觉得编程并不是一件枯燥的事情，自己可以利用所学的其它科的知识编一些有趣的程序，像下面的程序就不光用到编程知识，还用到高中的自由落体知识，当我们把所学知识都学以致用时，我们才是真正的掌握了知识．
　方法1
#include<graphics.h>
#include<dos.h>
#define g 10
main()
{int x=320,y,t;
 int gdriver=DETECT,gmode;
 initgraph(&gdriver,&gmode,"");
  cleardevice();
   setcolor(4);
   do{
    for(t=0;t<10;t++)
       {y=0.5*g*t*t;
         circle(x,y,20);

         delay(40000);
         cleardevice();
        }
    for(t=0;t<10;t++)
       {y=405-(90*t-0.5*g*t*t);
         circle(x,y,20);

         delay(40000);
         cleardevice();
        }
     }while(!kbhit());
     closegraph();
  }
方法2
#include<graphics.h>
#include<dos.h>
#define g 10
main()
 {int x=320,y,t;
   int size;
  int gdriver=DETECT,gmode;
    void *buffer;
  initgraph(&gdriver,&gmode,"");
  cleardevice();
 circle(320,10,10);
  size=imagesize(310,0,330,20);
  buffer=malloc(size);
  getimage(310,0,330,20,buffer);
  cleardevice();
  do{
       for(t=0;t<10;t++)
       {y=0.5*g*t*t;
        putimage(x,y,buffer,COPY_PUT);
        delay(40000);
        cleardevice();
        }
        for(t=0;t<10;t++)
       {y=405-(90*t-0.5*g*t*t);
        putimage(x,y,buffer,COPY_PUT);
        delay(40000);
        cleardevice();
        }
      }while(!kbhit());
    closegraph();
    }