Incircle of a triangle

#include
#include
#include
#include
# define pi 3.142857
# define round(a)((int)(a+0.5))
float xc,yc;
//))))))))))))))))
void ddaline(int x1,int y1,int x2,int y2,int col)
{ int steps,dx,dy,i;float xinc,yinc,x,y;
dx=x2-x1;
dy=y2-y1;
if(abs(dx)>abs(dy))
steps=abs(dx);
else
steps=abs(dy);
xinc=(float)dx/steps;
yinc=(float)dy/steps;
x=x1;y=y1;
putpixel(x,y,col);
for(i=0;i {
x=x+xinc;
y=y+yinc;
putpixel(round(x),round(y),col);
}
}
//)))))))))))))))
void parcir(int xc,int yc,float r,int sang,int eang,int col)
{ int k;
float x,y;

for(k=sang;k { x=xc+r*cos(pi*k/180);
y=yc+r*sin(pi*k/180);
putpixel(round(x),round(y),col);
}
}

void drawcir(int x,int y,float r,int sang)
{ int k=0;
int eang;
eang=sang+120;
while(k!=3)
{
parcir(x,y,r,sang,eang,(k+1));
sang=eang;
eang+=120;
k++;
}
}

//888888888888888888888888

void main()
{ int gd,gm;
detectgraph(&gd,&gm);
int x1,y1,x2,y2,x3,y3;float a,b,c,s,area,r;
initgraph(&gd,&gm,"..\\bgi");
printf("\n enter the co ordinates of the triangle");
scanf("%d",&x1);
scanf("%d",&y1);

printf("\n enter the co ordinates of the triangle");
scanf("%d",&x2);
scanf("%d",&y2);
printf("\n enter the co ordinates of the triangle");
scanf("%d",&x3);
scanf("%d",&y3);
cleardevice();
ddaline(x1,y1,x2,y2,YELLOW);
ddaline(x2,y2,x3,y3,YELLOW);
ddaline(x3,y3,x1,y1,YELLOW);

a=sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));

b=sqrt((x2-x3)*(x2-x3)+(y2-y3)*(y2-y3));
c=sqrt((x1-x3)*(x1-x3)+(y1-y3)*(y1-y3));
s=(a+b+c)/2;
area=sqrt(s*(s-a)*(s-b)*(s-c));
r=area/s;
xc=(x1*b+x2*c+x3*a)/(a+b+c);
yc=(y1*b+y2*c+y3*a)/(a+b+c);


while(!kbhit())
{ drawcir(round(xc),round(yc),r,i);
i++;
delay(1);
}


getch();

}