Creating a Curve in OpenGL using the equation y = x ^ 2

CurveOpenGL.cpp

/*
* Drawing the curve y = x ^ 2 in OpenGL 
* x ranges from (-10) to 10
* It's made to fit the entire Viewport
*/
#include <windows.h> // for MS Windows
#include <GL/glut.h> // GLUT, include glu.h and gl.h
#include <GL/gl.h>
/* Initialize OpenGL Graphics */
void initGL() {
// Set "clearing" or background color
	glClearColor(0.0f, 0.0f, 0.0f, 1.0f); // Black and opaque BackGround

	gluOrtho2D(-10.0, 10.0, 0.0, 100.0); // World View gluOrtho2d(left, right, bottom, top);
	glViewport(0, 0, 640, 480); // Is the View Port glViewport(left, bottom, width, height);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();

}


void display() {
	glClear(GL_COLOR_BUFFER_BIT); 
	
	GLdouble x;
	glBegin(GL_LINE_STRIP);
		for (x  = -10.0; x <= 10.0; x+= 0.1 ) {
			glVertex2d(x, x * x);
		}
	 
			
	glEnd();
	glFlush();
}
/* Main function: GLUT runs as a console application starting at main() */
int main(int argc, char** argv) {
	glutInit(&argc, argv); // Initialize GLUT
	glutCreateWindow(" y = x ^ 2"); // Create window with the given title
	glutInitWindowSize(320, 320); // Set the window's initial width & height
	glutInitWindowPosition(50, 50); // Position the window's initial top-left corner
	glutDisplayFunc(display); // Register callback handler for window re-paint event
	initGL(); // Our own OpenGL initialization
	glutMainLoop(); // Enter the event-processing loop
	return 0;
}