How to randomize the creation of objects of different classes? c++

I'm doing project with classes in c++ which consists of a car that avoids obstacles on a board. I want to randomize the appearance of the object of classes EnemiesCar, Nail, Hole (the last two are subclasses of the first). The problem is that when i generate random number, it change too fast and the object that had appeared then disappears (the objects on the board come out intermittently between other object because the random number changes too fast). How can I fix this problem? Are there other solution for randomize objects of class? (I tried to do this function in Game::randomAppear(EnemiesCar &myEn, Nail &myNe, Hole &myHo), below I leave only the class EnemiesCar because its subclasses are similar).

Game.cpp

#include "Game.h"
#include "Nail.h"
#include "EnemiesCar.h"
#include "Car.h"
#include "Hole.h"
#include <windows.h>
#include <iostream>
#include <thread>
#include <stdlib.h>     /* srand, rand */
#include <ctime>
using namespace std;

Game::Game(){
    running = true;
    counter = 100;
    maxScore = 0;
    maxLevel = 1;
    timeS = 100.0;
    level = 1;
    levelUp = 1000;
    levelDown = 0;
}

void Game::gotoXY(int x, int y)
{
    COORD coord;
    coord.X = x;
    coord.Y = y;
    SetConsoleCursorPosition(GetStdHandle(STD_OUTPUT_HANDLE), coord);
}

void Game::resetBoard()
{
    for(int j=0;j<20;j++){
        for(int i=1;i<20;i++){
            matrix[i][j]=0;
        }
    }
}

void Game::createTab()
{
    for(int j=0;j<20;j++){
        for(int i=0;i<21;i++){
            if(i==0 || i==20){
                    gotoXY(i,j);
                    cout<<"b";
            }else if(j == 19){
                    gotoXY(i,j);
                    cout<<"*";
            }else if(matrix[i][j]==1){
                    gotoXY(i,j);
                    cout<<"m";
            }else if(matrix[i][j]==2){
                    gotoXY(i,j);
                    cout<<"e";
            }else if(matrix[i][j]==3){
                    gotoXY(i,j);
                    cout<<"c";
            }else if(matrix[i][j]==4){
                    gotoXY(i,j);
                    cout<<"h";
            }else {
                gotoXY(i,j);
                cout<<" ";
            }
        }
    }
}



void Game::checkSamePosition(EnemiesCar EN, Nail NE)
{
    if(NE.xPos == EN.xPos && NE.yPos == EN.yPos){
        NE.xPos = NE.xPos + 2;
    }
}

int Game::checkMaxScore()
{
    if(maxScore < counter){
        maxScore = counter;
    }
    return maxScore;
}

int Game::checkMaxLevel()
{
    if(maxLevel < level){
        maxLevel = level;
    }
    return maxLevel;
}

void Game::TabLevelUp()
{
    system("cls");
    gotoXY(5, 5);
    cout << "Next Level" << endl;
    gotoXY(5, 7);
    cout << "Level: " << level;
}

void Game::TabLevelDown()
{
    system("cls");
    gotoXY(5, 5);
    cout << "Previous Level" << endl;
    gotoXY(5, 7);
    cout << "Level: " << level;
}

void Game::gameLevels(Car &car)
{
    if(counter == levelUp){
        level++;
        TabLevelUp();
        Sleep(5000);
        gotoXY(40, 9);
        cout << "level " << level;
        levelDown = levelUp;
        levelUp = levelUp + 1000;
        gotoXY(40, 10);
        cout << "next " << levelUp;
        if(timeS >= 40){
            double update = timeS - 20.0;
            timeS = update;
            gotoXY(40, 7);
            cout << "tmpIf " << timeS;
            Sleep(update);
        }else if(timeS == 20 || timeS == 30){
            double update = timeS - 10.0;
            timeS = update;
            gotoXY(40, 7);
            cout << "tmpIf " << timeS;
            Sleep(update);
        }else if(timeS >= 10 && timeS < 20){
            double update = timeS - 5.0;
            timeS = update;
            gotoXY(40, 7);
            cout << "tmpIf " << timeS;
            Sleep(update);
        }else if(timeS == 0){
            Sleep(timeS);
        }else{
            double update = timeS - 0.5;
            timeS = update;
            gotoXY(40, 7);
            cout << "tmpIf " << timeS;
            Sleep(update);
        }
        playGame(car);
    }else if(counter < levelDown){
        level--;
        TabLevelDown();
        Sleep(5000);
        levelUp = levelDown;
        levelDown = levelDown - 1000;
        if(timeS >= 40 && timeS < 100){
            double update = timeS + 20.0;
            timeS = update;
            gotoXY(45, 7);
            cout << "tmpIf " << timeS;
            Sleep(update);
        }else if(timeS == 20 || timeS == 30){
            double update = timeS + 10.0;
            timeS = update;
            gotoXY(45, 7);
            cout << "tmpIf " << timeS;
            Sleep(update);
        }else if(timeS == 10 && timeS < 20){
            double update = timeS + 5.0;
            timeS = update;
            gotoXY(45, 7);
            cout << "tmpIf " << timeS;
            Sleep(update);
        }else if(timeS < 10 && level <= 17){
            double update = timeS + 0.5;
            timeS = update;
            gotoXY(45, 7);
            cout << "tmpIf " << timeS;
            Sleep(update);
        }else{
            Sleep(timeS);
        }
        playGame(car);
    }else{
        Sleep(timeS);
    }
}

void Game::showLevelScore()
{
    gotoXY(50, 1);
    cout<<"Score: " << counter;
    gotoXY(50, 3);
    cout<<"Level: " << level;
}

void Game::gameEnd()
{
    if(counter <= 0){
        running = false;
        Sleep(1000);
        system("cls");
        gotoXY(5,4);
        cout << "GAME OVER!!!";
        gotoXY(5,6);
        cout << "MAX LEVEL: " << checkMaxLevel();
        gotoXY(5,7);
        cout << "MAX SCORE: " << checkMaxScore();
        gotoXY(0,0);
    }
}
int Game::generateRandomNumber()
{
    int rEne = rand() % 3;
    gotoXY(50, 5);
    cout << "R: " << rEne << endl;
    return rEne;
}

void Game::randomAppear(EnemiesCar &myEn, Nail &myNe, Hole &myHo)
{
    int rEne = generateRandomNumber();
    if(rEne == 0){
        myEn.appear();
        myEn.drawEnemies(myEn.xPos, myEn.yPos, matrix);
        myEn.move();
    }else if(rEne == 1){
        myNe.appear();
        myNe.drawNails(myNe.xPos, myNe.yPos, matrix);
        myNe.move();
    }else{
        myHo.appear();
        myHo.drawHoles(myHo.xPos, myHo.yPos, matrix);
        myHo.move();
    }
}


void Game::playGame(Car &mycar){

    EnemiesCar myEnmCar = EnemiesCar();
    Nail nails = Nail();
    Hole holes = Hole();

    while(this->running){

        srand (time(NULL));
        resetBoard();

        randomAppear(myEnmCar, nails, holes);
        
        checkSamePosition(myEnmCar, nails);

        /*myEnmCar.appear();
        myEnmCar.drawEnemies(myEnmCar.xPos, myEnmCar.yPos, matrix);
        myEnmCar.move();*/
        /*gotoXY(3, 22);
        cout << "enmpos: " << myEnmCar.xPos << myEnmCar.yPos << endl;*/

        /*nails.appear();
        nails.drawNails(nails.xPos, nails.yPos, matrix);
        nails.move();

        holes.appear();
        holes.drawHoles(holes.xPos, holes.yPos, matrix);
        holes.move();*/

        mycar.drawCar(mycar.xPos, mycar.yPos, matrix);
        mycar.checkCollusion(myEnmCar, nails, holes, &counter, &level);

        createTab();

        myEnmCar.addScore(mycar, &counter);
        nails.addScore(mycar, &counter);
        holes.addScore(mycar, &counter);


        showLevelScore();

        checkMaxLevel();
        checkMaxScore();

        gameEnd();

        gameLevels(mycar);

    }
}

void Game::startGame()
{
    srand (time(NULL));
    Car mycar = Car();


    thread myThread(&Car::myListener, &mycar, &mycar);


    playGame(mycar);


    Sleep(5000);


    myThread.detach();
}

EnemiesCar.h

#ifndef ENEMIESCAR_H
#define ENEMIESCAR_H
#include "Game.h"

class Game;
class Car;
class Nail;

class EnemiesCar
{
    public:
        const int xInit[9] = {2, 4, 6, 8, 10, 12, 14, 16, 18};
        int xPos;
        int yPos;
        Game games = Game();

        EnemiesCar();
        void appear();
        void drawEnemies(int x, int y, int myMatr[21][20]);
        //void draw();
        void move();
        void addScore(Car car, int *countScore);
};

#endif // ENEMIESCAR_H

EnemiesCar.cpp

#include <windows.h>
#include <iostream>
#include "EnemiesCar.h"
#include "Game.h"
#include "Car.h"
#include "Nail.h"
using namespace std;

EnemiesCar::EnemiesCar()
{
        int randomX = rand() % 6;
        xPos=xInit[randomX];
        yPos=0;
}

/*void EnemiesCar::drawEnemies(int x, int y)
{
    Game games = Game();
    if(y<20 && y>=-0){
        games.matrix[x][y] = 2;
        cout << "drawEne" <<endl;
    }
}*/

void EnemiesCar::appear()
{
    if(yPos==18){
        int randomNo = rand() % 21;
        /*games.gotoXY(35, 7);
        cout << "a: " << randomNo << " ";*/
        if(randomNo >= 0 && randomNo <= 3){
            xPos = 2;
        }else if(randomNo == 4 || randomNo == 5){
            xPos = 4;
        }else if(randomNo == 6 || randomNo == 7){
            xPos = 6;
        }else if(randomNo == 8 || randomNo == 9){
            xPos = 8;
        }else if(randomNo == 10 || randomNo == 11){
            xPos = 10;
        }else if(randomNo == 12 || randomNo == 13){
            xPos = 12;
        }else if(randomNo == 14 || randomNo == 15){
            xPos = 14;
        }else if(randomNo == 16 || randomNo == 17){
            xPos = 16;
        }else{
            xPos = 18;
        }
        yPos = -3;
    }
}

void EnemiesCar::drawEnemies(int x, int y, int myMatr[21][20])
{
    if(y<20 && y>=-0){
        myMatr[x][y] = 2;
        myMatr[x-1][y+1] = 2;
        myMatr[x+1][y+1] = 2;
        myMatr[x][y+1] = 2;
        myMatr[x][y+2] = 2;
    }
}

void EnemiesCar::move()
{
    yPos++;
}

void EnemiesCar::addScore(Car car, int *countScore)
{
    if((this->xPos <= car.xPos-3 && this->yPos == 16) || (this->xPos >= car.xPos+3 && this->yPos == 16)){
        *countScore = *countScore + 100;
    }
}