identify the functional & non functional requirements in this tic tac toe java code

import java.util.ArrayList;

import java.util.Arrays;

import java.util.List;

import java.util.Random;

import java.util.Scanner;

public class TicTacToe {

static ArrayListplayerPositions = new ArrayList();

static ArrayListcpuPositions = new ArrayList();

public static void main(String[] args) {

// TODO Auto-generated method stub

//create a game board

//printing game board

//3 spaces on the right & 3 spaces down (three rows and three columns)

//2D array of all symbols that we need for the tic tac toe

// symbols- char (characters)

char[][] gameBoard = {{' ', '|', ' ', '|',' '},

{'-', '+', '-', '+', '-'},

{' ', '|', ' ', '|', ' '},

{'-', '+', '-', '+', '-'},

{' ', '|', ' ', '|', ' '}};

printGameBoard(gameBoard);

// create a game loop

// get input from user

//store

//check if winner

while(true) {

Scanner scan = new Scanner(System.in);

System.out.println("Enter your Placement(1-9):");

int playerPos = scan.nextInt();

while(playerPositions.contains(playerPos) || cpuPositions.contains(playerPositions)) {

System.out.println ("position taken! Enter a correct position");

playerPos= scan.nextInt();

}

placePiece(gameBoard, playerPos, "player");

String result= checkWinner();

if (result.length() > 0) {

System.out.println(result);

break;

}

Random rand = new Random();

int cpuPos = rand.nextInt(9) + 1; //1-9

while(playerPositions.contains(cpuPos) || cpuPositions.contains(cpuPos)) {

cpuPos = rand.nextInt(9) + 1;

}

placePiece(gameBoard, cpuPos, "cpu"); //pas cpu position

printGameBoard(gameBoard);

result = checkWinner();

if (result.length() > 0) {

System.out.println(result);

break;

}

}

}

//print out the game board using 2 for loops

// for each row inside the game board

// for each char inside of the row

//print out symbol

// after each row print out line

//put for loop in method so it's not in the main method

public static void printGameBoard(char[][] gameBoard) {

for(char[] row : gameBoard) {

for (char c : row) {

System.out.print(c);

}

System.out.println();

}

}

public static void placePiece(char[][] gameBoard, int pos, String user) {

char symbol =' ';

if(user.equals("player")) {

symbol ='X';

playerPositions.add(pos);

} else if(user.equals("cpu")) {

symbol ='O';

cpuPositions.add(pos);

}

switch(pos) {

case 1:

gameBoard[0] [0] = symbol;

break;

case 2:

gameBoard[0] [2] = symbol;

break;

case 3:

gameBoard[0] [4] = symbol;

break;

case 4:

gameBoard[2] [0] = symbol;

break;

case 5:

gameBoard[2] [2] = symbol;

break;

case 6:

gameBoard[2] [4] = symbol;

break;

case 7:

gameBoard[4] [0] = symbol;

break;

case 8:

gameBoard[4] [0] = symbol;

break;

case 9:

gameBoard[4] [4] = symbol;

break;

default:

break ;

}

}

public static String checkWinner() {

List topRow= Arrays.asList(1, 2, 3);

List midRow= Arrays.asList(4, 5, 6);

List botRow = Arrays.asList(7, 8, 9);

List leftCol = Arrays.asList(1, 4, 7);

List midCol = Arrays.asList(2, 5, 8);

List rightCol= Arrays.asList(3, 6, 9);

List Cross1= Arrays.asList(1, 5, 9);

List Cross2= Arrays.asList(7, 5, 3);

List winning = new ArrayList();

winning.add(topRow);

winning.add(midRow);

winning.add(botRow);

winning.add(leftCol);

winning.add(midCol);

winning.add(rightCol);

winning.add(Cross1);

winning.add(Cross2);

for(List l : winning) {

if(playerPositions.containsAll(l)) {

return "Congratulations you won!";

} else if (cpuPositions.containsAll(l)) {

return "CPU WIns!~ Sorry:(";

} else if(playerPositions.size() + cpuPositions.size() ==9) {

return "CAT!";

}

}

return "";

}

}