Dev - C++ - Ayudita en el juego de tic tac toe.

Buenos días, me encuentro haciendo un juego de tic tac toe=X y Ceritos, para la clase de "Data Structure" pero tengo un pequeño problemita no logro ver por que en el modo de un solo jugador que es el único que esta entre " " funcional no completa el juego. Cualquier ayuda o comentario será bienvenido.
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//Header Files etc...
#include<iostream>
#include <stdio.h>
#include <stdlib.h>
using namespace std;

//Tic Tac Toe Grid matrix 3x3 declared As Global.
char matrix [3][3];

//Prototypes Area
inline void DisplayTitle(void); //Display Game Title using inline to gain speed.
void initialize_Matrix(void); //Initilize matrix with space.
void SinglePlayer(void); // Ask player One -X for a move.
void MultiPlayer(void);// 2 players
void get_player_move(void);//player ONE Moves
void DisplayGrid(void); //Display the area to be play on.
void TypeOfGame (void); //Select the type of game.
void GetComputerMove(void); //Computer Move
inline void Again(void);//Play Again?

char check();
char done;
//------------------------------------------->Main Start Here.
int main(int argc, char *argv[])
{

TypeOfGame();

system("PAUSE");
return EXIT_SUCCESS;
}
//------------------------------------------->END OF MAIN ();
//Function Declarations
inline void DisplayTitle(void) //Title Display
{
cout<<"\n\n\t\t Tic Tac Toe Game.\n\n";
};

void initialize_Matrix(void) //asignar espacios en blanco a la matrix
{
for(int x=0; x<3; x++)
{
for(int y=0; y<3; y++)
{
matrix[x][y]=' ';
}
}
};

void DisplayGrid(void)//Display the grin.
{
for(int t=0; t<3; t++)
{
printf("\t\t\t %c | %c | %c ",matrix[t][0],matrix[t][1],matrix [t][2]);
if(t!=2)
{
printf("\n\t\t\t---|---|---\n");
}
}
cout<<"\n";
};

void TypeOfGame(void)//Selection Single or Multiplayer.
{
int x=0;
cout<<endl;
DisplayTitle();
cout<<"\n\t\tOptions:"<<endl;
cout<<"\n\t\t1#Single Player.\n";
cout<<"\t\t2#Multi Player.\n";
cout<<"\t\t3#Exit the game.\n\n";
cout<<"\t\tEnter you're selection:";
cin>>x;

if (x==1)
{
system("CLS()");
SinglePlayer();
}
if (x==2)
{
system("CLS()");
MultiPlayer();
}
if (x==3)
{
cout<<"\t\tThaks for playing.\n\n";
EXIT_SUCCESS;//Exiting the game it works !!
}
if ((x==4)||(x==5)||(x==6)||(x==7)||(x==8)||(x==9)||(x==0))
{
cout<<"Invalid Entry...Press enter to continue.\n\n";
cout<<endl<<endl;
cout<<flush;
system("PAUSE()");
system("CLS()");
TypeOfGame();
}
else if (!x) //Arreglar esta desicion tiene que regresar
{
cout<<flush;
cout<<"Please read the options again...press enter.\n";
}
};

void SinglePlayer(void)//Single Player MODE.
{
do
{
system("CLS()");
DisplayTitle();
DisplayGrid();
get_player_move();
done=check();
if(done!= ' ')
{
break; /* winner!*/
}
GetComputerMove();
done = check(); /* see if winner */
}while (done==' ');
done =' ';
initialize_Matrix();

if(done=='X')
{
cout<<"You won!\n";
DisplayGrid();
system("PAUSE()");
Again();
}
else
{
cout<<"I won!!!!\n";
DisplayGrid();
system("PAUSE()");
Again();
} // show final positions

};

void MultiPlayer(void)
{
cout<<"\n\nThis part is not done yet, thanks for waiting."<<endl;
system("PAUSE()");
system("CLS()");
TypeOfGame();

};

void get_player_move(void)
{
signed short int x=0, y=0;
cout<<"\nWelcome, Player One! You're: X\n";
cout<<"Please enter the X and Y Coordinate to play:\n";
cout<<"x:";
cin>>x;
cout<<"y:";
cin>>y;
//matrix[x][y]='X';
if(matrix[x][y]== ' ')
{
cout<<system("CLS()");
cout<<"Invalid move, try again.\n";
get_player_move();
}
else matrix[x][y] = 'X';
};

void GetComputerMove() //Computer Artificial Intelligence.
{
int x,y;
for(x=0; x<3; x++)
{
for(y=0; y<3; y++)
{
if(matrix[x][y]==' ')
{
break;
}
}
}

if(x*y==9)
{
cout<<"DRAW!\n";
Again();
}
else
matrix[x][y] = 'O';
};

char check()
{
int i;

for(i=0; i<3; i++) /* check rows */
{
if(matrix[i][0]==matrix[i][1] && matrix[i][0]==matrix[i][2])
{
return matrix[i][0];
}
}
for(i=0; i<3; i++) /* check columns */
{
if(matrix[0][i]==matrix[1][i] && matrix[0][i]==matrix[2][i])
{
return matrix[0][i];
}
}
/* test diagonals */
if(matrix[0][0]==matrix[1][1] && matrix[1][1]==matrix[2][2])
{
return matrix[0][0];
}
if(matrix[0][2]==matrix[1][1] && matrix[1][1]==matrix[2][0])
{
return matrix[0][2];
}
else
{
return ' ';
}
};

inline void Again(void) //Ask the user to play again.
{
system("CLS()");
signed short int x=0;
cout<<"\n\n\t Do you want to pay again?\n";
cout<<"\n\t\t1=Yes, 2=No\n";
cout<<"\t\tDesition:";
cin>>x;
cout<<endl;
if (x==1)
{
system("CLS()");
TypeOfGame ();
}
if (x==2)
{
EXIT_SUCCESS;
//system("CMD(EXIT)");
}
};

Oye nose si podria saber si me pudieras mandar un codigo completo para que funcione en este juego del tic-tac-toe lo que pasa es que es un proyecto final y pues ocuparia un poco de ayuda para poderlo elaborar