Advance a loop without waiting for a key press but have the option to accept it.

This is the source code for a game where you catch 'o's with a U.
It only makes the 'o's fall and generate every key press.
I want to make it so that the function "void advance(input)" is activated WITHOUT a key press every 200 milliseconds but will accept input if a key is pressed.

I am also planning on adding more stuff but this is a problem I really want to fix.

Code:

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#include "stdafx.h"#include <iostream>
#include <stdlib.h>
#include <time.h>
#include <stdio.h>
#include <conio.h>
#include <windows.h>
#include <WinSock.h>
#define LEFT_ARROW 75
#define RIGHT_ARROW 77


using namespace std;


char grid[2][8];
void advance(char input);
int o_spawn;
int score = 0;
void o_fall();
void wait(int);
int count;
char input;




int _tmain(int argc, _TCHAR* argv[])
{


    char input = '\0';
    grid[0][0] = ' ';
    grid[1][0] = ' ';


    unsigned short int menu_choice = 3;
    while (menu_choice !=2)
    {
        // asks if you want to play
        cout << "Would you like to play?\n";
        cout << "1: YES\n";
        cout << "2: NO\n";
        cin >> menu_choice;
       


        // checks your answer
        while (menu_choice == 1)
        {
           
            // advances the os and generates them
            cout << "\n\n\n\n\n\n\n\n\n\n\n\n";
            // starts loop of typing the arrow key
                do
                {
                    input = getch();
                    //moves 'u' to the left
                    if (input == LEFT_ARROW)
                    {
                        grid [0][7] = 'U';
                        grid [1][7] = ' ';
                        advance(input);
                        input = getch();
                    }
                    // moves u to the right
                    else if (input == RIGHT_ARROW)
                    {
                        grid [0][7] = ' ';
                        grid [1][7] = 'U';
                        advance(input);
                        input = getch();
                    }
                    else if (input == 'q' || input == 'Q')
                    {
                        cout << "It seems you wan't to quit... okay.\nPress any button to quit.\n";
                        char quit;
                        quit = getch();
                        return 0;
                    }
                    else
                    {
                        advance(input);
                    }
            }while (input != 'q' || 'Q');
        }
    }
    return 0;
}


void advance(char input)
{
        //makes 'o's generate randomly
        int change_o_space = rand() % 10 + 1;
        if ((change_o_space == 3) && (grid[0][0] == ' '))
        {
            grid[0][0] = 'o';
        }
        else if ((change_o_space == 6) && (grid[1][0] == ' '))
        {
            grid[1][0] = 'o';
        }
        //advances o to the bottom of screen
        o_fall();
        //prints the board
        cout << grid[0][0];
        cout << grid[1][0] << endl;
        cout << grid[0][1];
        cout << grid[1][1] << endl;
        cout << grid[0][2];
        cout << grid[1][2] << endl;
        cout << grid[0][3];
        cout << grid[1][3] << endl;
        cout << grid[0][4];
        cout << grid[1][4] << endl;
        cout << grid[0][5];
        cout << grid[1][5] << endl;
        cout << grid[0][6];
        cout << grid[1][6] << endl;
        cout << grid[0][7];
        cout << grid[1][7] << endl;
        cout << "SCORE:" << score;
        cout << "\n\n\n\n\n\n\n\n\n\n";
}


// makes 'o's fall and increments the score
void o_fall()
{
    // generates 'o's
    if (grid[0][6] == 'o' && grid[0][7] == 'U')
    {
        grid[0][6] = ' ';
        // increases score
        score++;
    }
    // generates 'o's
    if (grid[1][6] == 'o' && grid[1][7] == 'U')
    {
        grid[1][6] = ' ';
        // increases score
        score++;
    }


    //advances 'o's
    if (grid[0][7] == 'o')
    {
        grid[0][7] = ' ';
    }
    if (grid[1][7] == 'o')
    {
        grid[1][7] = ' ';
    }
    if (grid[0][6] == 'o')
    {
        grid[0][6] = ' ';
        grid[0][7] = 'o';
    }
    if (grid[1][6] == 'o')
    {
        grid[1][6] = ' ';
        grid[1][7] = 'o';
    }
    if (grid[0][5] == 'o')
    {
        grid[0][5] = ' ';
        grid[0][6] = 'o';
    }
    if (grid[1][5] == 'o')
    {
        grid[1][5] = ' ';
        grid[1][6] = 'o';
    }
    if (grid[0][4] == 'o')
    {
        grid[0][4] = ' ';
        grid[0][5] = 'o';
    }
    if (grid[1][4] == 'o')
    {
        grid[1][4] = ' ';
        grid[1][5] = 'o';
    }
    if (grid[0][3] == 'o')
    {
        grid[0][3] = ' ';
        grid[0][4] = 'o';
    }
    if (grid[1][3] == 'o')
    {
        grid[1][3] = ' ';
        grid[1][4] = 'o';
    }
    if (grid[0][2] == 'o')
    {
        grid[0][2] = ' ';
        grid[0][3] = 'o';
    }
    if (grid[1][2] == 'o')
    {
        grid[1][2] = ' ';
        grid[1][3] = 'o';
    }
    if (grid[0][1] == 'o')
    {
        grid[0][1] = ' ';
        grid[0][2] = 'o';
    }
    if (grid[1][1] == 'o')
    {
        grid[1][1] = ' ';
        grid[1][2] = 'o';
    }
    if (grid[0][0] == 'o')
    {
        grid[0][0] = ' ';
        grid[0][1] = 'o';
    }
    if (grid[1][0] == 'o')
    {
        grid[1][0] = ' ';
        grid[1][1] = 'o';
    }
}

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Sorry this was so long.
Yes I know there are improvements and simplifications that can easily be made.
This code was rushed though and I'm not very experienced in c++ nor am I familiar with most of the libraries.
This is a console application compiled with Visual Studio on Windows 7 Professional 64 bit.

So this is my question here:
I want to make it so that the function "void advance(input)" is activated WITHOUT a key press every 200 milliseconds but will accept input if a key is pressed.

Try _kbhit (CRT)

Code:

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while (1) {
    if (_kbhit()) {
        int key = _getch();
        // ...
    }
    // ...
}

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