Code of Tic Tac Toe Playing Against Computer

#include<iostream>

using namespace std;

int grid[3][3];

int y1 , y2;

void initialize(char b[3][3])
{

cout<<"PLAYER - 1 [X]\t PLAYER - 2 [O]\n\n";

cout<<"\t\t     |     |     \n";

cout<<"\t\t "<<b[0][0]<<"   | "<<b[0][1]<<"   | "<<b[0][2]<<"    \n";

cout<<"\t\t_____|_____|_____\n";

cout<<"\t\t     |     |     \n";

cout<<"\t\t  "<<b[1][0]<<"  |  "<<b[1][1]<<"  | "<<b[1][2]<<"  \n";

cout<<"\t\t_____|_____|_____\n";

cout<<"\t\t     |     |     \n";

cout<<"\t\t  "<<b[2][0]<<"  |  "<<b[2][1]<<"  | "<<b[2][2]<<"  \n";

cout<<"\t\t     |     |    \n";

}

void display()
{

    char b[3][3];

    for(int i=0;i<3;i++)    {

        for(int j=0;j<3;j++)        {

        if(grid[i][j]== 0)      {

            b[i][j] = ' ';

        }

            else if(grid[i][j]==10) {

                b[i][j] ='X';

            }

            else if(grid[i][j]== -10)   {

                b[i][j] ='O';

            }

        }

    }   

    initialize(b);

}

int winningposiblity()
{

    int w1=0,w2=0;

    

    for(int i=0;i<3;i++)    {   

    if  (grid[i][0]+grid[i][1]+grid[i][2]==20

     || grid[i][0]+grid[i][1]+grid[i][2]==10)

     

                w1++;

                

                

    else if  (grid[i][0]+grid[i][1]+grid[i][2]== -20 

    || grid[i][0]+grid[i][1]+grid[i][2]== -10)

    

                w2++;

        

            

    if  (grid[0][i]+grid[1][i+1]+grid[i][i+2]==20

     || grid[0][i]+grid[1][i+1]+grid[i][i+2]==10)

     

                w1++;

                

    else if  (grid[0][i]+grid[1][i+1]+grid[i][i+2]== -20

     || grid[0][i]+grid[1][i+1]+grid[i][i+2]== -10)

                w2++;   

    }

    if  (grid[0][0]+grid[1][1]+grid[2][2]==20

     || grid[0][0]+grid[1][1]+grid[2][2]==10)

     

        w1++;

        

    else if  (grid[0][0]+grid[1][1]+grid[2][2]== -20

     || grid[0][0]+grid[1][1]+grid[2][2]== -10)

     

        w2++;

    if  (grid[0][2]+grid[1][1]+grid[2][0]==20

     || grid[0][2]+grid[1][1]+grid[2][0]==10)

     

        w1++;

        

    else if  (grid[0][2]+grid[1][1]+grid[2][0]== -20

     || grid[0][2]+grid[1][1]+grid[2][0]== -10)

     

        w2++;

    return w2-w1;   

}

int anyof(int player,int i1,int i2,

        int j1,int j2,int k1,int k2)
{

    

    if(grid[i1][i2]==0 && 

    grid[j1][j2]==grid[k1][k2] && grid[j1][j2]==player) 

    {

        grid[i1][i2]= -10;

        cout<<"Computer's move : "<<i1*3+i2+1<<endl;

        return 1;

    }

    

    if(grid[j1][j2]==0 &&

     grid[i1][i2]==grid[k1][k2] && grid[i1][i2]==player)

    {

        grid[j1][j2]= -10;

        cout<<"Computer's move : "<<j1*3+j2+1<<endl;

        return 1;

    }

    

    if(grid[k1][k2]==0 && 

    grid[i1][i2]==grid[j1][j2] && grid[j1][j2]==player) 

    {

        grid[k1][k2]= -10;

        cout<<"Computer's move : "<<k1*3+k2+1<<endl;

        return 1;

    }

    

    return 0;

}

int isplayerwinning(int player)
{

    

    if(anyof(player,0,0,1,1,2,2) ||

     anyof(player,0,2,1,1,2,0))

     

        return 1;

    for(int i=0;i<3;i++)    {

        

        if(anyof(player,i,0,i,1,i,2))

            return 1;

        if(anyof(player,0,i,1,i,2,i))

            return 1;

    }

    return 0;

}

void player2()
{

    

    if(isplayerwinning(-10) ||

     isplayerwinning(10))

     

        return;

        

    int max=0,a=0,b=0;

    for(int i=0;i<3;i++)    {

        for(int j=0;j<3;j++)    {

            if(grid[i][j]==0)   {

                grid[i][j]= -10;

                

            

                int heuristic=winningposiblity();

                if(heuristic>max)

                {

                    max= heuristic;

                    a=i;

                    b=j;

                }

                grid[i][j]=0;

            }

        }

    }

    grid[a][b]= -10;

    cout<<"Computer's move : "<<a*3+b+1<<endl;

}

int iswin()
{

    

    if(grid[0][0]==grid[1][1] && 

    grid[1][1]==grid[2][2] && grid[0][0]!=0)

    

        return grid[0][0];

    

    if(grid[0][2]==grid[1][1] && 

    grid[1][1]==grid[2][0] && grid[0][2]!=0)

    

        return grid[0][2];

    

    for(int i=0;i<3;i++)    {

        if(grid[i][0]==grid[i][1] && 

        grid[i][1]==grid[i][2] && grid[i][0]!=0)

        

            return grid[i][0];

        

        if(grid[0][i]==grid[1][i] && 

        grid[1][i]==grid[2][i] && grid[0][i]!=0)

            return grid[0][i];

    }

    return 0;

}

void playGame()
{

    cout<<"********************** TIC TAC TOE "<<

    "**********************"<<endl;

    for(int i=0;i<3;i++)    {

        for(int j=0;j<3;j++)

            (grid[i][j] = 0);

    }

    

    int turn=1,flag=0;

    int total=9;

    while(total--)  {

        int w=iswin();

        if(w!=0)    {

            if(w==10)   {

                y1++;

                cout<<"*****Congratulations!!! "<<

                "You won the game*****"<<endl<<endl;

            }

            

            else    {

                y2++;

                cout<<"********Sorry!!! "<<

                "Computer won the game********"<<endl<<endl;

            }

            flag=1;

            break;

        }

        if(turn==1) {

            int a,b,c;

            cout<<"Player's move : ";

            cin>>c;

            a=(c-1)/3;

            b=(c-1)%3;

            grid[a][b]=10;

            turn =2;

        }

        

        else    {

            player2(); //computer

            turn=1;

        }

        

        cout<<"DISPLAY:"<<endl;

        display();

        cout<<endl;

    }

    if(flag==0) {

        cout<<"-----------DRAW----------"<<endl<<endl;

    }

    

}

int main()
{

    

bool z = true;

int choice;

while(z)    {

 cout<<"1: New Game \t2: View Score \t3: End Game\n";

 cin >> choice;

 switch(choice) {

    case 1:

        playGame();

        break;

    

    case 2:

     cout<<"You - "<< y1 <<" Computer - "<< y2 << "\n";     

      break;

    

    case 3:

        z = false;

        break;

            

    default:

        cout<<"Try Again!!";

        break;
  }

}
return 0;
}

Contributor:-

Gaurav Waghmare