// author : bini

// compiled using Linux GCC and SDL libgraph and lm flags

// to compile in terminal : gcc mw.c -lgraph -lm

#include "stdio.h"

#include "stdlib.h"

#include "graphics.h"

#include "math.h"

#define pi M_PI

// xc and yc are centers

// x and y are spoke ka array

int xc=100,yc=100,x[100],y[100];

int main(){

int gd = DETECT , gm ;

int a,i, n,r=40;

double rotate_angle = 0 , t = 0;

// inputs

printf("Enter radius and spokes\n");

scanf("%d %d",&r,&n);

// initialization graphs

initgraph(&gd,&gm,"");

setcolor(3);

a = xc + r;

while(!kbhit()){

while(a<=630){ // so as to ensure that the wheel doesnt run out of the page

t = pi*rotate_angle / 180;

cleardevice();

circle(xc,yc,r);

// use polar coordinates to rotate.. !!

for(i=0;i<n;i++,rotate_angle+=360/n){

// now moving of wheel takes place in two steps;;;

// rotation and translation

// note: only the center of mass of any circular body will undergo translation motion

// whereas the boundary of the body will undergo rotation motion.

// we are first finding the angle by which each spoke rotaotes and the we rotate the spoke

t = pi*rotate_angle/180;

x[i] = xc+ r*cos(t);

y[i] = yc + r*sin(t);

line(xc,yc,x[i],y[i]);

}

rotate_angle+=2; // for next frame ,, ...

xc+=2; // translating the center of circle

a=xc+r;

delay(20);

}

// xc = 100 ; a = xc+r; // uncomment this line if u wanna continous rotation

}

getchar();

closegraph();

}