using System;

using System.Collections.Generic;

​

public class Program

{

    bool notFinished = true;

    int player = 2;

​

    List<int[]> grid = new List<int[]>

    {

        new int[] { 0, 0, 0, 0, 0, 0, 0 },

        new int[] { 0, 0, 0, 0, 0, 0, 0 },

        new int[] { 0, 0, 0, 0, 0, 0, 0 },

        new int[] { 0, 0, 0, 0, 0, 0, 0 },

        new int[] { 0, 0, 0, 0, 0, 0, 0 },

        new int[] { 0, 0, 0, 0, 0, 0, 0 },

        new int[] { 0, 0, 0, 0, 0, 0, 0 }

    };

​

    public int switchPlayer(int nextPlayer)

    {

        if (nextPlayer == 1)

        {

            nextPlayer = 2;

            player = 2;

        }

        else

        {

            nextPlayer = 1;

            player = 1;

        }

​

        return nextPlayer;

    }

​

    public void printGrid()

    {

        for (int i = 0; i < grid.Count; i++)

        {

            for (int p = 0; p < grid[i].Length; p++)

            {

                Console.Write(grid[i][p] + "  ");

            }

            Console.Write("\n\n");

        }

    }

​

    public bool isWin(int column, int row, int player)

    {

        int count = 0;

        bool isWon = false;

        int maxColumn = grid.Count;

        int maxRow = grid[0].Length;

​

        //horizontal check

        for (int i = 0; i < maxColumn; i++)

        {

            if (grid[column][i] == player) {

                count++;

                if (count >= 4) { isWon = true; }

            }

            else { count = 0; }

        }

        count = 0;

​

        //vertical check

        for (int i = 0; i < maxRow; i++)

        {

            if (grid[i][row] == player)

            {

                count++;

                if (count >= 4) { isWon = true; }

            }

            else { count = 0; }

        }

        if (count >= 4) { isWon = true; }

        count = 0;

​

        //down diagonal check (left side)

        for (int colStart = 0; colStart < maxColumn - 3; colStart++)

        {

            int col = colStart;

            row = 0;

            for (; col < maxColumn && row < maxRow; col++, row++)

            {

                if (grid[col][row] == player)

                {

                    count++;

                    if (count >= 4) { isWon = true; }

                }

                else { count = 0; }

            }

        }

        if (count >= 4) { isWon = true; }

        count = 0;

​

        //down diagonal check (right side)

        for (int rowStart = 0; rowStart < maxRow - 3; rowStart++)

        {

            int col = 0;

            row = rowStart;

            for (; col < maxColumn && row < maxRow; col++, row++)

            {

                if (grid[col][row] == player)

                {

                    count++;

                    if (count >= 4) { isWon = true; }

                }

                else { count = 0; }

            }

        }

        if (count >= 4) { isWon = true; }

        count = 0;

​

        //up diagonal check (left side)

        for (int colStart = grid.Count - 1; colStart > maxColumn - 5; colStart--)

        {

            int col = colStart;

            row = 0;

            for (; col >= 0 && row < maxRow; col--, row++)

            {

                if (grid[col][row] == player)

                {

                    count++;

                    if (count >= 4) { isWon = true; }

                }

                else { count = 0; }

            }

        }

        if (count >= 4) { isWon = true; }

        count = 0;

​

        //up diagonal check (right side)

        for (int rowStart = 1; rowStart < maxRow - 4; rowStart++)

        {

            int col = grid.Count - 1;

            row = rowStart;

            for (; col >= 0 && row < maxRow; col--, row++)

            {

                if (grid[col][row] == player)

                {

                    count++;

                    if (count >= 4) { isWon = true; }

                }

                else { count = 0; }

            }

        }

        if (count >= 4) { isWon = true; }

        count = 0;

​

        return isWon;

    }

​

    public void Main()

    {   

        while (notFinished)

        {

            int currentPlayer = switchPlayer(player);

            Console.Write("\n\n");

​

            printGrid();

​

            Console.WriteLine("Enter column to insert into: (1-7)");

            string columnSelected = Console.ReadLine();

​

            for (int i = 0; i < grid[Convert.ToInt32(columnSelected) - 1].Length; i++)

            {

                if (grid[Convert.ToInt32(columnSelected) - 1][i] == 0)

                {

                    grid[Convert.ToInt32(columnSelected) - 1][i] = currentPlayer;

                    if (isWin(Convert.ToInt32(columnSelected) - 1, i, currentPlayer))

                    {

                        printGrid();

                        Console.WriteLine("Player " + player + " wins!");

​

                        notFinished = false;

                    }

                    break;

                }

            }

        }

    }

}