chess broad drawing using opengl and glut by c++

Chess broad drawing using OpenGl  and glut by c++

#include<windows.h>
#include<gl\glut.h>
int c = 1;
void init()
{
// For displaying the window color
glClearColor(1, 1, 1, 0);
// Choosing the type of projection
glMatrixMode(GL_PROJECTION);
// for setting the transformation which here is 2D
gluOrtho2D(0, 800, 0,600);
}

void drawSquare(GLint x1, GLint y1, GLint x2, GLint y2, GLint x3, GLint y3, GLint x4, GLint y4)
{
// if color is 0 then draw white box and change value of color = 1
if (c == 1)
{
glColor3f(0, 0, 1); // white color value is 1 1 1
c = 0;
}
// if color is 1 then draw black box and change value of color = 0
else
{
glColor3f(1, 1, 0); // black color value is 0 0 0
c = 1;
}

// Draw Square
glBegin(GL_POLYGON);
glVertex2i(x1, y1);
glVertex2i(x2, y2);
glVertex2i(x3, y3);
glVertex2i(x4, y4);
glEnd();
}
void chessboard()
{
glClear(GL_COLOR_BUFFER_BIT); // Clear display window
GLint x, y;

for (x = 0; x <= 800; x += 100)
{
for (y = 0; y <= 600; y += 75)
{
drawSquare(x, y + 75, x + 100, y + 75, x + 100, y, x, y);
}
}
// Process all OpenGL routine s as quickly as possible
glFlush();
}

int main(int agrc, char ** argv)
{
// Initialize GLUT
glutInit(&agrc, argv);
// Set display mode
glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
// Set top - left display window position.
glutInitWindowPosition(100, 100);
// Set display window width and height
glutInitWindowSize(800, 600);
// Create display window with the given title
glutCreateWindow("");
// Execute initialization procedure
init();
// Send graphics to display window
glutDisplayFunc(chessboard);
// Display everything and wait.
glutMainLoop();
}

chess borad