How to make basic TicTacToe game in C

/*
  Tic Tac Toe game - tictacto.c
  Author : Zahid Wadiwale
  This is a simple Tic Tac Toe game. I have used conio2.h that is not a part of
  the C standard and not available in Dev-C++ by default.
  Please let me know if you find and error or if you have any questions.
  I have also attached libconio.a , libconio_unicode.a and conio2.h
  Enjoy!
*/

#include <stdio.h>
#include <conio2.h>
#include<windows.h>
#define UPARROW     72
#define DOWNARROW   80
#define LEFTARROW   75
#define RIGHTARROW  77
#define ENTER       13
#define QUIT       'q'

int _x,_y; //To track the position of the Tic Tac Toe frame being drawn

//Function to show the Tic Tac Toe Frame
void showframe(int posx, int posy)
{
  int hr=196, vr=179; // These are ascii character which display the lines
  int crossbr=197;    // Another ascii character
  int x=posx, y=posy;
  int i,j;
  gotoxy(35,4); cprintf("TIC TAC TOE \n by Zahid Wadiwale");
  gotoxy(35,5); for(i=0;i<11;i++) cprintf("%c",223);

  for(i=0;i<2;i++)
  {
    for(j=1;j<=11;j++)
     {
      gotoxy(x,y);
      printf("%c",hr);
      x++;
     }
    x=posx; y+=2;
  }
  x=posx+3; y=posy-1;
  for(i=0;i<2;i++)
  {
   for(j=1;j<=5;j++)
   {
      gotoxy(x,y);
      printf("%c",vr);
      y++;
   }
   x+=4;y=posy-1;
  }

  x=posx+3; y=posy;
  gotoxy(x,y);
  printf("%c",crossbr);
   x=posx+7; y=posy;
  gotoxy(x,y);
  printf("%c",crossbr);
  x=posx+3; y=posy+2;
  gotoxy(x,y);
  printf("%c",crossbr);
  x=posx+7; y=posy+2;
  gotoxy(x,y);
  printf("%c",crossbr);
}

//Function to fill random values into the array
void fillrandom(char arr[3][3])
{
  int i=0,j=0;
  char ch='A';
  for(i=0;i<3;i++)
   { for(j=0;j<3;j++)
     { arr[i][j] = ch; ch++; }
   }
}

//Function to show the character in the specified box
void showbox(char ch, int box)
{
   switch(box)
   {
     case 1 : gotoxy(_x+1,_y-1); printf("%c",ch); break; //1st box
     case 2 : gotoxy(_x+5,_y-1); printf("%c",ch); break; //2nd box
     case 3 : gotoxy(_x+9,_y-1); printf("%c",ch); break; //3rd box
     case 4 : gotoxy(_x+1,_y+1); printf("%c",ch); break; //4th box
     case 5 : gotoxy(_x+5,_y+1); printf("%c",ch); break; //5th box
     case 6 : gotoxy(_x+9,_y+1); printf("%c",ch); break; //6th box
     case 7 : gotoxy(_x+1,_y+3); printf("%c",ch); break; //7th box
     case 8 : gotoxy(_x+5,_y+3); printf("%c",ch); break; //8th box
     case 9 : gotoxy(_x+9,_y+3); printf("%c",ch); break; //9th box
   }
}

//Function to insert the specified character into the array
void putintobox(char arr[3][3], char ch, int box)
{
  switch(box)
  {
    case 1 : if(arr[0][0] != 'X' && arr[0][0]!= 'O')
                { arr[0][0] = ch;
            showbox(ch,1);
          }
          break;
    case 2 : if(arr[0][1] != 'X' && arr[0][1]!= 'O')
          { arr[0][1] = ch;
            showbox(ch,2);
          }
          break;
    case 3 : if(arr[0][2] != 'X' && arr[0][2]!= 'O')
                { arr[0][2] = ch;
            showbox(ch,3);
          }
          break;
    case 4 : if(arr[1][0] != 'X' && arr[1][0]!= 'O')
         { arr[1][0] = ch;
           showbox(ch,4);
         }
          break;
    case 5 : if(arr[1][1] != 'X' && arr[1][1]!= 'O')
          { arr[1][1] = ch;
           showbox(ch,5);
          }
          break;
    case 6 : if(arr[1][2] != 'X' && arr[1][2]!= 'O')
          { arr[1][2] = ch;
                  showbox(ch,6);
          }
          break;
    case 7 : if(arr[2][0] != 'X' && arr[2][0]!= 'O')
           { arr[2][0] = ch;
            showbox(ch,7);
          }
          break;
    case 8 : if(arr[2][1] != 'X' && arr[2][1]!= 'O')
          { arr[2][1] = ch;
            showbox(ch,8);
          }
          break;
    case 9 : if(arr[2][2] != 'X' && arr[2][2]!= 'O')
          { arr[2][2] = ch;
            showbox(ch,9);
          }
          break;
   }//end of switch
}

//Function to show the curson on the box specified
//uses the position to check the coordinates
void gotobox(int box)
{
  switch(box)
  {
    case 1 : gotoxy(_x+1,_y-1); break;
    case 2 : gotoxy(_x+5,_y-1); break;
    case 3 : gotoxy(_x+9,_y-1); break;
    case 4 : gotoxy(_x+1,_y+1); break;
    case 5 : gotoxy(_x+5,_y+1); break; //5th box
    case 6 : gotoxy(_x+9,_y+1); break; //6th box
    case 7 : gotoxy(_x+1,_y+3); break; //7th box
    case 8 : gotoxy(_x+5,_y+3); break; //8th box
    case 9 : gotoxy(_x+9,_y+3); break;
  }
}

//Function to handle the navigation
int navigate(char arr[3][3], int box, int player, int key)
{
   switch(key)
   {
     case UPARROW    : if( (box!=1) || (box!=2) || (box!=3) )
                 { box-=3; if(box<1) box = 1; gotobox(box); }
                    break;
     case DOWNARROW  : if( (box!=7) || (box!=8) || (box!=9) )
                 { box+=3; if(box>9) box = 9; gotobox(box); }
                 break;
     case LEFTARROW  : if( (box!=1) || (box!=4) || (box!=7) )
                 { box--;  if(box<1) box = 1; gotobox(box); }
                 break;
     case RIGHTARROW : if( (box!=3) || (box!=6) || (box!=9) )
                 { box++; if(box>9) box = 9; gotobox(box); }
                 break;
     case ENTER      : if(player == 0)
               putintobox(arr,'O',box);
                 else if(player == 1)
               putintobox(arr,'X',box);
                 break;
    }//end of switch(key)
 return box;
}
int checkforwin(char arr[3][3])
{
  int w=0;
/*  0,0   0,1   0,2
    1,0   1,1   1,2
    2,0   2,1   2,2
*/
  //rows
  if((arr[0][0] == arr[0][1]) && (arr[0][1] == arr[0][2])) w = 1;
  else if((arr[1][0] == arr[1][1]) && (arr[1][1] == arr[1][2])) w = 1;
  else if((arr[2][0] == arr[2][1]) && (arr[2][1] == arr[2][2])) w = 1;
  //coloums
  else if((arr[0][0] == arr[1][0]) && (arr[1][0] == arr[2][0])) w = 1;
  else if((arr[0][1] == arr[1][1]) && (arr[1][1] == arr[2][1])) w = 1;
  else if((arr[0][2] == arr[1][2]) && (arr[1][2] == arr[2][2])) w = 1;
  //diagonal
  else if((arr[0][0] == arr[1][1]) && (arr[1][1] == arr[2][2])) w = 1;
  else if((arr[0][2] == arr[1][1]) && (arr[1][1] == arr[2][0])) w = 1;
  return w;
}

int boxesleft(char a[3][3])
{
   int i,j,boxesleft=9;
   for(i=0;i<3;i++)
    { for(j=0;j<3;j++)
      { if((a[i][j] == 'X') ||(a[i][j] == 'O'))
          boxesleft--;
      }
    }
   return boxesleft;
}

int main()
{
  SetConsoleTitle("Calculator Project - by Zahid Wadiwale");
  char arr[3][3];
  char player[3][30],O_OR_X[2],ch;
  int  x,y,turns,chance,enter,box,win,quit,winner;
  int  movesfinished = 0;
  O_OR_X[0] = 'O'; O_OR_X[1] = 'X';
  do{
   textbackground(7); textcolor(0); //Set the specified background and textcolor
   clrscr(); //Clears the screen - defined in conio.h(conio2.h)
  _x = 35; _y = 12;
   x = _x; y = _y;
  showframe(x,y); //Draws the frame of Tic Tac Toe
  showbox('O',1); //Displays O in box 1
  showbox('X',2); //Displays X in box 2
  showbox('O',3); //Displays O in box 3
  showbox('X',4); //Displays X in box 4
  showbox('O',5); //Displays O in box 5
  showbox('X',6); //Displays X in box 6
  showbox('O',7); //Displays O in box 7
  showbox('X',8); //Displays X in box 8
  showbox('O',9); //Displays O in box 9
  gotoxy(2,18);
  printf("Welcome to Tic Tac Toe");
  printf("\n Rules are simple. Navigate to the box with arrow keys [%c %c %c %c] and hit enter.",30,31,17,16);
  printf("\n If you try to overwrite a box, then your chance will be passed on.");
  printf("\n This game is crested by Zahid Wadiwale");
  fillrandom(arr); //Filling random character to the array
  printf("\n Player 1, enter your name: "); gets(player[0]); //Get player1's name
  printf(" Player 2, enter your name: ");   gets(player[1]); //Get player2's name
  printf("\n %s, you have been given O             %s, you have been given X",player[0],player[1]);
  printf("\n Lets begin ( press any key )"); getch();

  turns  = 0;  //to count the total number of turns
  chance = 0;  //to check whose chance is it
  enter  = 0;  //variable to track if Enter was pressed
  box    = 1;  //Track the current box number
  win    = 0;  //Check if someone won
  quit   = 0;  //Check if player wants to quit
  winner = 10; //To see who is the winner


  clrscr();
  showframe(x,y);
  while((!win))
  {

     gotoxy(2,20);
     printf("%s(%c), its your chance.     ",player[chance],O_OR_X[chance]);
     while(!enter && !quit)
     {
     if(kbhit())
   {
     ch = getch();
     switch(ch)
     {
       case UPARROW    :  box=navigate(arr,box,chance,UPARROW);
                  break;
       case DOWNARROW  :  box=navigate(arr,box,chance,DOWNARROW);
                 break;
       case LEFTARROW  :  box=navigate(arr,box,chance,LEFTARROW);
                 break;
       case RIGHTARROW :  box=navigate(arr,box,chance,RIGHTARROW);
                 break;
       case ENTER      :  box=navigate(arr,box,chance,ENTER);
                 enter=1; break;
       case QUIT       :  quit = 1; break;
     }//end of switch(ch)
  }//end of if(kbhit())
     }//end of while
     if(quit) break;   //Quits the program
     if(chance == 0)
      { putintobox(arr,box,'O'); box = 1; } //player1
     else if(chance == 1)
      { putintobox(arr,box,'X'); box = 1; } //player2
     if( (win = checkforwin(arr)) == 1)
      winner = chance;
     if(chance == 1) chance = 0;
     else chance = 1;
     enter = 0;
     turns++;
     if(!boxesleft(arr))
      movesfinished = 1;
     //If its a draw
     if((!win) && (turns==9) && (movesfinished))
      break;
  }//end of while(win)
  if(win)
  { gotoxy(22,22);
    textbackground(4); textcolor(15);
    if(winner == 0)
     cprintf(" Congratulations %s, you win the game! ",player[0]);
    else
     cprintf(" Congratulations %s, you win the game! ",player[1]);
  }
  else if(quit)
   {
      gotoxy(10,22);
      textbackground(4); textcolor(15);
      cprintf(" Ok, lets play again sometime. See you later. Press any key to exit.\n\n");
      getch();
      return 1;
   }
  else if((!win) && (turns==9) && (movesfinished))
  { gotoxy(22,22);
    printf("No one wins. Its a draw.");
  }
   printf("\n\n Do you want to play again? (Y/N): "); ch = getch();

  }while(ch=='Y' || ch=='y'); //playagain
  return 0;
}