tic tac toe please help.

[Fallenfantasy182]

Hi, I posted earlier about a programming assignment for school I am doing. I am in year twelve, and am doing software design as a subject. Before I posted a really terrible piece of coding full of errors, which i developed initially for the project. With the help of a friend, the code was able to become error free. however, I compile it and I go to run it, and when I run it, it executes to the part where players enter names, the player names are displayed, and space thats created.

//SDD 2012
//Tic tac toe
//l

#include <iostream>
#include <string>

using namespace std;

string playerone;
string playertwo;

//variables for spaces in the game board
char G;
char Grid[9];

//tic tac toe board for game play
char Print_Grid (char G)
{
    cout << "__________________________\n";
    cout << "         |        |        \n";
    cout <<  Grid [0] && "|" && Grid [1] && "|" && Grid [2];
    cout << "         |        |        \n";
    cout << "__________________________\n";
    cout << "         |        |        \n";
    cout <<  Grid [3] && "|" && Grid [4]&& "|" && Grid [5];
    cout << "         |        |        \n";
    cout << "__________________________\n";
    cout << "         |        |        \n";
    cout <<  Grid [6] && "|" && Grid [7] && "|" && Grid [8];
    cout << "         |        |        \n";
    cout << "__________________________\n";


//if array has been filled then the game has ended
int number_of_moves = 0;

//to determine whose turn it is
char current_turn = '0';

//if winner has been found
bool foundwinner = false;

//check if game is over
bool gameover = false;

//main function
int main ()
{
    cout << "Tic Tac Toe";
    cout << "   begin   ";

    //allowing user to enter name and be identified by own name
    cout << "player one enter name\n";
    cin >> playerone;
    cout << "player two enter name\n";
    cin >> playertwo;

    //so player names can be shown on the screen.
    cout << playerone << "          " << playertwo << endl;


    Print_Grid(G);

    //while loop
    while (gameover == false)
    {
        void determine_turn();
        void get_move();
        void check_win();
    }


    return 0;

}

void determine_turn()
{
    playerone = 'X';
    playertwo = 'O';

    if (current_turn == 'X') //if X just had a turn change to O
    {
        current_turn = 'O';
    }
    else
    {
        current_turn = 'X';
    }


}


void get_move ()
{
    int move;
    if (current_turn == 'X')
    {
        cout << playerone << "select a location for 'X'" << endl;
        cin >> move;

        if (move == 1)
        {
            Grid[0] = 'X';
        }
        if (move == 2)
        {
            Grid[1] = 'X';
        }
        if (move == 3)
        {
            Grid[2] = 'X';
        }
        if (move == 4)
        {
            Grid[3] = 'X';
        }
        if (move == 5)
        {
            Grid[4] = 'X';
        }
        if (move == 6)
        {
            Grid[5] = 'X';
        }
        if (move == 7)
        {
            Grid[6] = 'X';
        }
        if (move == 8)
        {
            Grid[7] = 'X';
        }
        if (move == 9)
        {
            Grid[8] = 'X';
        }
    }
    else
    {
        cout << playertwo << "select location for '0'" << endl;
        cin >> move;

        if (move == 1)
        {
            Grid[0] = 'O';
        }
        if (move == 2)
        {
            Grid[1] = 'O';
        }
        if (move == 3)
        {
            Grid[2] = 'O';
        }
        if (move == 4)
        {
            Grid[3] = 'O';
        }
        if (move == 5)
        {
            Grid[4] = 'O';
        }
        if (move == 6)
        {
            Grid[5] = 'O';
        }
        if (move == 7)
        {
            Grid[6] = 'O';
        }
        if (move == 8)
        {
            Grid[7] = 'O';
        }
        if (move == 9)
        {
            Grid[8] = 'O';
        }
    }
}


void check_win()
{
    if
    (
        ((Grid[0] == Grid[3]) && (Grid[0] == Grid[6])) ||
        ((Grid[1] == Grid[4]) && (Grid[1] == Grid[7])) ||
        ((Grid[2] == Grid[3]) && (Grid[2] == Grid[8])) ||
        ((Grid[0] == Grid[3]) && (Grid[0] == Grid[2])) ||
        ((Grid[3] == Grid[3]) && (Grid[3] == Grid[5])) ||
        ((Grid[6] == Grid[3]) && (Grid[6] == Grid[8])) ||
        ((Grid[0] == Grid[3]) && (Grid[0] == Grid[8])) ||
        ((Grid[2] == Grid[3]) && (Grid[2] == Grid[6]))
    )
    {
        foundwinner = true;
        if (current_turn == '0')
        {
            cout << "the winner is" << playerone << endl;
        }
        else
        {
            cout << "the winner is" << playertwo << endl;
        }
    }
    else
    {
        foundwinner = false;

        if (foundwinner = true && number_of_moves == 9)
        {
            gameover = true;
        }
    }
}

[ResidentBiscuit]

char Grid[9]; Not initialized with anything.
cout << Grid [0] && "|" && Grid [1] && "|" && Grid [2]; The ampersands in here, why? I think you were wanting to use operator<< instead. Not even sure what that does.
char Print_Grid (char G) Why are you passing in G? It's never used.

Might wanna stop using global variables, also. There's also better ways to do all of this, but I'll leave that to you to figure out :D That's the fun part

[o1vk4iN6]

Some of these are very overcomplicated...

        if (move == 1)
        {
            Grid[0] = 'O'; // try to notice pattern, Grid[ x ], where x is the same as (move - 1), all this can be simplified to one line of code
        }
        if (move == 2)
        {
            Grid[1] = 'O';
        }

// 50 lines later 

[Fallenfantasy182]

one line of code?