Resizing my simple OpenGL/GLUT window creates strange lines - c++

Question

I recently created my first GLUT window and gave it a white background and somewhere for a camera to look at.
Anyway, I resize my window and I got these strange lines. It seemed like it glitched and captured recent fragments of my desktop screen. Here is my screenshot link on imgur:
http://i.imgur.com/gSRWnc5.png
Sorry if the picture was a little oversized, but I was wondering if there was a fix to that weird glitch.
Here is my code:
#include <OpenGL/OpenGL.h>
#include <GLUT/GLUT.h>
void display(void) {
glClearColor(1.0, 1.0, 1.0, 1.0);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
gluLookAt (0.0, 0.0, 5.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
glFlush();
}
int main (int argc, char **argv) {
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE);
glutInitWindowSize(400, 400);
glutInitWindowPosition(100, 100);
glutCreateWindow("My First GLUT/OpenGL Window");
glutDisplayFunc(display);
glutMainLoop();
return 0;
}

Answer 1

You get those weird glitches because you don't resize your viewport. What you need to do is create a callback function for glutReshapeFunc in which you call glViewport to resize your viewport. Then, you need to call glutPostRedisplay in order to re-execute your display function.
On a side note, if you want your display function to be executed constantly, use glutIdleFunc along side glutDisplayFunc.
Cheers!