Moving circle Program in c++ language

#include<stdio.h>

#include<conio.h>


#include<math.h>


#include<stdio.h>


#include<stdlib.h>


#include<iostream>


#include<graphics.h>


#include<conio.h>


#include<malloc.h>


#define timedelay 20



using namespace std;


int xy[800][2]; 

void getpoints(int ,int ,int ,int );


int main()

{  
initwindow(800,600,"Vishal Grade");


label1:

for(;;)

{

static int a=abs((rand()%(700)+500));

static int b= abs((rand()%(500)+500));



int c= abs((rand()%(700)+50));    

int d= abs((rand()%(500)+50));     




xy[0][0]=a;

xy[0][1]=b;

getpoints(a,b,c,d);

int s=rand()%15;

for(int i=0;i<c-a;i++)

{

cout<<xy[i][0]<<"\t"<<xy[i][1]<<endl;

if(50<=xy[i][0] &&xy[i][0]<=750 && 50<=xy[i][1] && xy[i][1]<=550)

{

for(int j=0;j<50;j++)

{

circle(xy[i][0],xy[i][1],j);

circle(xy[i][0],xy[i][1],50-j);

setcolor(rand()%10+5);

}

setcolor(rand()%10+5);

setbkcolor(s);           //background color

delay(timedelay);

}

else {

delay(timedelay*3);

goto label1;

}



putpixel(xy[i][0],xy[i][1],3);



cleardevice();



}

a=c;

b=d;



}

getch();

}
void getpoints(int x1,int y1,int x2,int y2) 

{                                         


float m=float(y2-y1)/(x2-x1); 


if(x1<=x2)           

{
{

float y0;

int x0=1;

int step=x2-x1;    

y0=m;   

int i=1;

static float t=xy[0][1];

while(i<=step)

{

xy[i][0]=xy[i-1][0]+x0;

t=t+y0;

xy[i][1]=int(round(t));

i++;
 

}}




}



else

{          

int y0;

float x0;

if(m<=0)

{

x0=1/m;

y0=1;


}


else


{


x0=-1/m;


y0=-1;


}


int step=y2-y1;


int i=1;


static float t=xy[0][0];


while(i<=step)


{


t=t+x0;

xy[i][0]=int(round(t));

xy[i][1]=xy[i-1][1]+y0;

i++;


}


} 





}