Thread: Drawing to code 5 point star function C++

I'm trying to code a 5 point star function in C++, I am using the WinBGIm library. I am getting stuck on the trigonometry of the triangle. My function is given the centre x and y coordinates and the radius of the star all as integers.

This is what I have s ofar.

Code:

// The main purpose of this program is to draw 7 stars
// Using the WinBGIm graphics library.

// Directives:
#include <graphics.h>
#include <cstdlib>
#include <cmath>
using namespace std;

//Constants

const int S = 700;

// First Star(test)
const int STARX1 = 0.2*S;
const int STARY1 = 0.5*S;
const int RADIUS1 = 0.07*S;


//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
// Function Prototypes.
// This is a list of all the functions that I plan to write because the
// author of the graphics library did not have them!
void star (int cx, int cy, int radius);
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
// Main program

int main()
{
    initwindow(S,S,"Dipper!");
    star(STARX1, STARY1, RADIUS1);
    delay(200000);

}

//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
// This function draws a star. The center of the star is at (cx, cy),
// and the radius of the star is given by radius.

void star(int cx, int cy, int radius)
{
    
    int farrightxcoord = cx + radius*cos(M_PI/10);
    int farrightycoord = cy - radius*sin(M_PI/10);
    int bottomrightxcoord = cx+ radius*cos(5*M_PI/10);
    int bottomrightycoord= cy - radius*sin(5*M_PI/10);
    int bottomleftxcoord = cx+radius*cos(9*M_PI/10);
    int bottomleftycoord=cx-radius*sin(9*M_PI/10);
    int farleftxcoord    = cx + radius*cos(13*M_PI/10);
    int farleftycoord    = cy - radius*sin(13*M_PI/10);
    int topxcoord = cx + radius*cos(17*M_PI/10);
    int topycoord = cy - radius*sin(17*M_PI/10);
    line(farrightxcoord,farrightycoord, farleftxcoord, farleftycoord);
    line(farrightxcoord,farrightycoord, bottomleftxcoord,bottomleftycoord);
    line(bottomleftxcoord,bottomleftycoord,topxcoord,topycoord);
    line(topxcoord,topycoord,bottomrightxcoord,bottomrightycoord);
    line(bottomrightxcoord,bottomrightycoord, farleftxcoord, farleftycoord);

As you can see the star function is where I am really confused, can someone help me with this?