PieChart in C Language

#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>
#include <math.h>

void draw_circle(int,int,int);
void draw_piechart();

int main(void)
{

   int midx, midy, r;

   midx = 320;
   midy = 240;

   clrscr();

   draw_piechart(r);

   getch();
   closegraph();
   return 0;
}



void draw_circle(int radius, int midx, int midy)
{
int x,y,pk;


x=0;
y=radius;

pk=1-radius;

while(x<=y)
{
           // For all quadrants

   putpixel((midx+x),(midy-y),15);
   putpixel((midx+x),(midy+y),15);
   putpixel((midx-x),(midy-y),15);
   putpixel((midx-x),(midy+y),15);
   putpixel((midx-y),(midy+x),15);
   putpixel((midx-y),(midy-x),15);
   putpixel((midx+y),(midy+x),15);
   putpixel((midx+y),(midy-x),15);



   if (pk<0)
   {
pk=pk+(2*x)+1;
   }
   else
   {
pk=pk+(2*x)+1-(2*y);
y-=1;
   }
   x+=1;
}


}

void draw_piechart()
{

int data,i,length,left=100,cnt=0,angle[5],x1,y1,x2,y2,no,midx,midy,r=90,y,newx1,newx2,newy1,newy2,diffx,diffy;
   int gdriver = DETECT, gmode, errorcode;


for(i=0;i<5;i++)
{
if(left>0)
{
printf("\n Enter data for %d part from %d %: ",i+1,left);
scanf("%d",&data);

left-=data;
angle[i]=((360*data)/100);
cnt++;
}

}



midx=320;
midy=240;
initgraph(&gdriver, &gmode, "c:\\tc\\BGI");

// To draw a circle
draw_circle(r,midx,midy);


x1=320;
y1=240;
x2=320;
y2=240;

i=0;
line(x1,y1,x2,y2-r);
newx1=x2;
newy1=y2-r;

// Radius = 90
no=angle[i];
while(cnt>1)
{

if(no<=180)
{

y=(r)-no;
length=sqrt(pow(r,2)-pow(y,2));

x2=midx+length;
y2=(midy-r)+no;

}
else
{

y=(r*3)-no;

length=sqrt(pow(r,2)-pow(y,2));

x2=midx-length;
y2=(240+r)-(no-180);

}


cnt--;

line(x1,y1,x2,y2);

i++;
no+=angle[i];

}


}