#include<stdio.h>
#include<graphics.h>
#include<dos.h>
#include<math.h>

int tower[3][10];// the three towers' disks as stack
int top[3];//top of the three stacks
int from,to;//moving 'from' tower number 'to' tower number
int diskInAir;//number of disk moved (1 to n)
int l,b,u;

void push(int to, int diskno)
//putting disk on tower
{
tower[to-1][++top[to-1]]=diskno;
}

int pop(int from)
//take topmost disk from tower
{
return(tower[from-1][top[from-1]--]);
}

void drawStill()
{
int j,i,disk;
cleardevice();
for(j=1;j<=3;j++)
 {
 //draw tower
 setfillstyle(CLOSE_DOT_FILL,WHITE);
 bar(j*l,u,j*l+5,b);
 //draw all disks on tower
 for(i=0;i<=top[j-1];i++)
  {
  disk=tower[j-1][i];
  setfillstyle(SOLID_FILL,1+disk);
  bar(j*l-15-disk*5,b-(i+1)*10,j*l+5+15+disk*5,b-i*10);
  }
 }
}

void animator()
//to show the movement of disk
{
int x,y,dif,sign;
diskInAir=pop(from);
x=from*l;
y=b-(top[from-1]+1)*10;
//taking disk upward from the tower
for(;y>u-20;y-=15)
 {
 drawStill();
 setfillstyle(SOLID_FILL,1+diskInAir);
 bar(x-15-diskInAir*5,y-10,x+5+15+diskInAir*5,y);
 delay(10);
 }
y=u-20;
dif=to*l-x;
sign=dif/abs(dif);
//moving disk towards a target tower
for(;abs(x-to*l)>25;x+=sign*15)
 {
 drawStill();
 setfillstyle(SOLID_FILL,1+diskInAir);
 bar(x-15-diskInAir*5,y-10,x+5+15+diskInAir*5,y);
 delay(10);
 }
x=to*l;
//placing disk on a target tower
for(;y<b-(top[to-1]+1)*10;y+=15)
 {
 drawStill();
 setfillstyle(SOLID_FILL,1+diskInAir);
 bar(x-15-diskInAir*5,y-10,x+5+15+diskInAir*5,y);
 delay(10);
 }
push(to,diskInAir);
drawStill();
}

void moveTopN(int n, int a, int b, int c)
//Move top n disk from tower 'a' to tower 'c'
//tower 'b' used for swapping
{
if(n>=1)
 {
 moveTopN(n-1,a,c,b);
 drawStill();
 delay(1000);
 from=a;
 to=c;
 //animating the move
 animator();
 moveTopN(n-1,b,a,c);
 }
}

int main()
{
int i,gd=DETECT,gm,n;
printf("Enter number of disks");
scanf("%d",&n);
initgraph(&gd,&gm,"C:\\TURBOC3\\BGI\\");
//setting all tower empty
for(i=0;i<3;i++)
 {
 top[i]=-1;
 }
//putting all disks on tower 'a'
for(i=n;i>0;i--)
 {
 push(1,i);
 }
l=getmaxx()/4;
b=getmaxy()-50;
u=getmaxy()/3+100;
//start solving
moveTopN(n,1,2,3);
delay(4000);
getch();
}