code not finished but whenever I try to run the code all I see is a black screen I dont see any of the lines or the x drawings that I made? : I'm creating a tic tac toe game in open gl Im not finished yet but whenever I run my code all I see is a black screen I do not see the lines that I have drawn or the X?

#include<stdlib.h>

#include<math.h>

#include<time.h>

#include<string.h>

#include <GLut/glut.h>

using namespace std;

int matrix [3][3]; // board for the gameplay of tic tac toe we are using a 3x3 matrix board

int turn; // indicates whose turn it is going to be

bool gameover; // is the game over would you like to end the game

int result;// the ending result of the game

void begin()

{
    
    turn=1;
    
    for(int i=0;i<3;i++) // setting up the board and clearing the matrix we start at 1, basically clearing our matrix
        
        
        
    {
        
        for(int j=0;j<3;j++)
            
            
            
            matrix[i][j]=0;
        
    }
    
}

void drawxo() // setting up our X and O if it is 1 then we want to use x and if it is 2 then 0

{
    
    for(int i = 0; i <= 2; i++)
        
    {
        
        for(int j = 0; j <= 2; j++)
            
        {
            
            if(matrix[i][j] == 1) //if it is 1 then draw x
                
            {
                
                glBegin(GL_LINES);
                
                glVertex2f(50 + j * 100 - 25, 100 + i * 100 - 25);
                
                glVertex2f(50 + j * 100 + 25, 100 + i * 100 + 25);
                
                glVertex2f(50 + j * 100 - 25, 100 + i * 100 + 25);
                
                glVertex2f(50 + j * 100 + 25, 100 + i * 100 - 25);
                
                glEnd();
                
            }
            
            else if(matrix[i][j] == 2) //if it is 2 then draw o
                
            {

                glBegin(GL_LINE_LOOP);
                
                glVertex2f(50 + j * 100 - 25, 100 + i * 100 - 25);
                
                glVertex2f(50 + j * 100 - 25, 100 + i * 100 + 25);
                
                glVertex2f(50 + j * 100 + 25, 100 + i * 100 + 25);
                
                glVertex2f(50 + j * 100 + 25, 100 + i * 100 - 25);
                
                glEnd();
                
            }
            
        }
        
    }
    
}

void DrawString(void *font,const char s[],float x,float y)

{
    
    unsigned int i;
    
    glRasterPos2f(x,y);
    
    for(i=0;i<strlen(s);i++)
        
    {
        
        glutBitmapCharacter(font,s[i]);
        
    }
    
}

void drawLines()

{
    
    glBegin(GL_LINES);
    
    glColor3f(0, 0, 0);
    
    //2 vertical lines
    
    glVertex2f(100, 50);
    
    glVertex2f(100, 340);
    
    glVertex2f(200, 340);
    
    glVertex2f(200, 50);
    
    //2 horizontal lines
    
    glVertex2f(0, 150);
    
    glVertex2f(300, 150);
    
    glVertex2f(0, 250);
    
    glVertex2f(300, 250);
    
    glEnd();
    
}

void display()

{
    
    glClear(GL_COLOR_BUFFER_BIT);
    
    glClearColor(1, 1, 1, 1);
    
    glColor3f(0, 0, 0);
    
    if(turn == 1)
        
        DrawString(GLUT_BITMAP_HELVETICA_18, "Player1's turn", 100, 30);
    
    
    
    drawxo();
    
    drawLines();
    
    
    
    
    
    
    
    
    
    glutSwapBuffers();
    
    
    
}

void KeyPress(unsigned char key, int x, int y)

{
    
    
    
    switch (key)
    
    {
            
        case 27: // the escape key to exit the program
            
            exit (0);
            
            break;
            
            
            
        case 'y':
            
            
            
            if (gameover = true) {
                
                gameover = false;
                
                begin();
                
            }
            
            break;
            
            
            
        case 'n' :
            
            if (gameover = true) {
                
                exit(0);
                
            }
            
            break;
            
    }
    
}

int main(int argc, char **argv)

{
    
    begin();
    
    glutInit(&argc,argv);
    
    glutInitDisplayMode(GLUT_RGB|GLUT_DOUBLE);
    
    glutInitWindowPosition(550,200);
    
    glutInitWindowSize(300,350);
    
    glutCreateWindow("Tic tac toe");
    
    glutDisplayFunc(display);
    
    glutKeyboardFunc(KeyPress);
    
    glutIdleFunc(display);
    
    glutMainLoop();
    
    
    
}




