Paint

Trying to make paint pallet like tutorial and editing it 

i keep getting  unresolved external symbol _main referenced in function "int __cdecl invoke_main(void)" (?invoke_main

and error with `selectedColour;` it should containt the selected color from the array of struct colour

#include <GL\glew.h>
#include <GL\freeglut.h>

class ColourPalette {
struct Colour {
 float r, g, b;
};
public:

// Array of colours in the palette
static const Colour colours[];
static const Colour selectedColour;
// index of selected colour in above array
static int selectedIndex;
// x position of the palette, based on window width
static int palette_x_pos;


/*
 Draws the colour palette on …