Rotation Of Both Two Linked Arm Simultaneously of the Robot

#include<stdio.h>
#include<GRAPHICS.h>
#include<math.h>
double radian(int val)
{
  return (M_PI*val)/180;
}

void rotate(int x_c,int y_c,int a,int b,double *x_p,double *y_p,int degree)
{
   double rad=radian(degree);
   *x_p=((a-x_c)*cos(rad))-((b-y_c)*sin(rad))+x_c;
   *y_p=((a-x_c)*sin(rad))+((b-y_c)*cos(rad))+y_c;
}

int main()
{
   double lx[3],ly[3],a,b,c,d;
   int degree1,degree2;

  /* request auto detection */
   int gdriver = DETECT, gmode, errorcode;

  /* initialize graphics mode */
  initgraph(&gdriver, &gmode, "C:\\TurboC3\\BGI");

   lx[0]=getmaxx()/2;
   ly[0]=getmaxy()/2;

   lx[1]=lx[0]+110;
   ly[1]=ly[0];

   lx[2]=lx[1];
   ly[2]=ly[1]-50;

   degree1=5,degree2=30;
   while(!kbhit())
   {

      rotate(lx[0],ly[0],lx[1],ly[1],&a,&b,degree1);
      lx[1]=a;
      ly[1]=b;
      rotate(lx[0],ly[0],lx[2],ly[2],&a,&b,degree1);
      lx[2]=a;
      ly[2]=b;
      setcolor(BLUE);
      line(lx[0],ly[0],lx[1],ly[1]);

      rotate(lx[1],ly[1],lx[2],ly[2],&a,&b,degree2);
      lx[2]=a;
      ly[2]=b;
      setcolor(RED);
      line(lx[1],ly[1],lx[2],ly[2]);

      delay(1000);
      setcolor(BLACK);
      line(lx[0],ly[0],lx[1],ly[1]);
      line(lx[1],ly[1],lx[2],ly[2]);

       // degree1+=10;
       // degree2+=30;
       // if(degree1>360)
       // degree1=0;
       // if(degree2>360)
       // degree2=0;

    }
   getch();

   return 0;
   }

Output :