I'm having trouble putting who wins in my game

Question

So everything in my code works so far, but I don't know why the checkWinner function doesn't work. In my Bool checkWinner function, I used bool. When I call the function I'm not sure where to put it as well.

What I tried: one place where I have tried was in my for loop in the main function. Ex:

checkWinner(board, gwinner)

However it doesn't work, the game keeps on playing when someone even has three X's or O's.

Possible problems I see: I'm not sure what's wrong, could it be my checkwinner function, or could it be my playerChoice function?

The question is why isn't a winner being picked? Thank you for the help.

#include <iostream>
#include <string>
using namespace std;

const int ROWS = 3; // For the rows
const int COLS = 3; // For the number of columns;
void showBoard(const char[][COLS], int); // Shows the board
void playerChoice(char[][COLS], char); // shows the player choice
bool checkwinner(const char[][COLS], string);

int main()
{
    char board[ROWS][COLS] = { { '*', '*', '*' }, { '*', '*', '*' }, { '*', '*', '*' } };
    string gwinner = " ";
    showBoard(board, 3); // displays the board

    for (int i = 0; i < 4; i++) {
        playerChoice(board, 'X');
        showBoard(board, 3);

        playerChoice(board, 'O');
        showBoard(board, 3);
    }

    cout << "The winner is: " << gwinner;
}

void showBoard(const char arr[][COLS], int SIZE)
{
    for (int row = 0; row < SIZE; row++) {
        for (int col = 0; col < SIZE; col++)
            cout << '|' << arr[row][col];
        cout << '|' << endl;
    }
}

void playerChoice(char arr[][COLS], char name)
{
    int row, columns;
    char board[ROWS][COLS] = { { '*', '*', '*' }, { '*', '*', '*' }, { '*', '*', '*' } };

    cout << "What row would you like?\n";
    cout << "Row: ";
    cin >> row;

    while (row < 1 || row > 3) {
        cout << "Error please pick a row between 1 and 3.\n";
        cout << "Row: ";
        cin >> row;
        cout << endl;
    }

    cout << "What column would you like?\n";
    cout << "Column: ";
    cin >> columns;

    while (columns < 1 || columns > 3) {
        cout << "Error,please pick a column between 1 and 3.\n";
        cout << "Column: ";
        cin >> columns;
        cout << endl;
    }

    if (arr[row - 1][columns - 1] == '*') {
        arr[row - 1][columns - 1] = name;
    }
    else {
        cout << "This space is occupied.\n";
        cout << "Please select again\n";
    }
}

bool checkwinner(const char arr[][COLS], string gwinner)
{
    bool winner = false;

    if ((arr[0][0] == arr[0][1]) && (arr[0][1] == arr[0][2])) // checks row
    {
        winner = true;
    }
    else if ((arr[1][0] == arr[1][1]) && (arr[1][1] == arr[1][2])) // checks row
    {
        winner = true;
    }
    else if ((arr[2][0] == arr[2][1]) && (arr[2][1] == arr[2][2])) // checks row
    {
        winner = true;
    }
    else if ((arr[0][0] == arr[1][0]) && (arr[1][0] == arr[2][0])) // checks columns
    {
        winner = true;
    }
    else if ((arr[0][1] == arr[1][1]) && (arr[1][1] == arr[2][1])) // checks columns
    {
        winner = true;
    }
    else if ((arr[0][2] == arr[1][2]) && (arr[1][2] == arr[2][2])) // checks columns
    {
        winner = true;
    }
    else if ((arr[0][0] == arr[1][1]) && (arr[1][1] == arr[2][2])) // checks diagonal
    {
        winner = true;
    }
    else if ((arr[2][0] == arr[1][1]) && (arr[1][1] == arr[0][2])) // checks diagonal
    {
        winner = true;
    }
    else {
        gwinner = "It's a tie! ";
        winner = false;
    }

    return winner; // returns the winner
}