Thread: Discuss this code with me ..."Connect4 game"

hello everyone
this assignment is exercise to Control Structures and this is my try!!
I hope if you degree this

package connect4;
 
import java.util.Scanner;
 
/**
 *
 * @author HanyMoh.
 */
public class Connect4 {
 
    public static void main(String[] args) {
        Scanner S = new Scanner(System.in);
 
        System.out.println("Welcome to connect4");
        System.out.println("Select game type");
        System.out.println("Enter 1 for \"Player vs. Computer\"");
        System.out.println("Enter 2 for \"Player vs. Player\"");
 
        // prepar empty board //****************************/
        char[][] board = new char[6][7];
        for (int i = 0; i < board.length; i++) {
            for (int j = 0; j < board[i].length; j++) {
                board[i][j] = ' '; // one space = empty input             
            }//endfor j            
        }//endfor i
 
        // select game type //*****************************/
        int game_type = S.nextInt(); // [1]= player+cpu , [2]=player+player
        System.out.println("Starting game");
 
        char input;
        int turn = 1;// turn42
        boolean x = true;
        while (x = true) {
            if (turn % 2 == 1) {
                System.out.print("Player 1: ");
                input = 'X';//input player1
            } else {
                System.out.print("Player 2: ");
                input = 'O';// input player2
            }
 
            int col;
            if (game_type == 1 && turn % 2 == 0) {
                col = 1 + (int) (Math.random() * 7); // cpu player
                System.out.println(col);
            } else {
 
                // input col index           
                col = S.nextInt();
                if (col < 1 || col > 7) {
                    System.out.println("Invalid place, play again");
                    continue; // to play again
                }
            }
            col--; // because input equal index
 
            // input row index
            int row = 5; // last index row
            // get count of all inputs in col           
            for (int i = 0; i < board.length; i++) {
                if (board[i][col] == 'X' || board[i][col] == 'O') {
                    row--;
                }
            }
            //if full col
            if (row < 0) {
                System.out.println("Invalid place, play again");
                continue; // to play again
            }
 
            // insert the input by row & col
            board[row][col] = input;
 
            // print board 
            System.out.println(" 1 | 2 | 3 | 4 | 5 | 6 | 7 |");
 
            for (int i = 0; i < board.length; i++) {
                for (int j = 0; j < board[i].length; j++) {
                    System.out.print(" " + board[i][j] + " |");
                }//endfor j
                System.out.println();
            }//endfor i
 
            turn++;
 
 
            /**
             * ************* checks **************
             */
            if (turn > 42) {// 6×7=42 full board inputs
                System.out.println("Draw!");
                break;
            }
 
            // check col 
            int count = 0;
            for (int i = 0; i < board.length; i++) {
                if (board[i][col] == input) {
                    count++; // count if sequance
                    if (count == 4) {
                        break;
                    }//end if
                } else {
                    count = 0; //not sequance start again
                }//end if
            }
 
            if (count != 4) {
                count = 0;// start count again
 
                // check row
                for (int i = 0; i < board[row].length; i++) {// row length
                    if (board[row][i] == input) {
                        count++; // count if sequance
                        if (count == 4) {
                            break;
                        }// if=4
                    } else {
                        count = 0; //not sequance start again
                    }//if = input
                }//endfor
            }// if<> 4
 
            if (count != 4) {
                count = 0;
 
                // check diagonal[\] 
                int down = board.length - row - 1;
                int r = row + down;
                int c = col + down;
 
                // if out of board range
                while (r >= 0 && c >= 0) {
                    if (!(c <= 6) || !(r <= 5)) {
                        c--;
                        r--;
                        continue;
                    }
 
                    // check count of diagonal
                    if (board[r][c] == input) {
                        count++;
                        if (count == 4) {
                            break;
                        }
                    } else {
                        count = 0;
                    }
                    // move up
                    r--;
                    c--;
                }// end while
 
            }
 
            if (count != 4) {
                count = 0;
 
                // check secnd diagonal[/] 
                int up = board.length - row - 1;
                int rw = row + up;
                int cl = col - up;
 
                // if out of board range
                while (rw >= 0 && cl >= 0) {
                    if (!(cl <= 6) || !(rw <= 5)) {
                        cl++;
                        rw--;
                        continue;
                    }
 
                    // check count of diagonal
                    if (board[rw][cl] == input) {
                        count++;
                        if (count == 4) {
                            break;
                        }
                    } else {
                        count = 0;
                    }
                    // move up
                    rw--;
                    cl++;
                }// end while
 
            }// end if 
 
            // print winner player
            if (count >= 4) {
                int player = 1;
                if (turn % 2 == 1) {
                    player = 2;
                }
                System.out.println("Player " + player + " is the Winner!");
                break;
            }// if print
 
        }//end while
    }//end main
}// end class

Some random thoughts:

That's a lot of code to have in one method, but perhaps you haven't learned how to add more methods yet.

It seems to run okay, but I chose '2' for the Player vs. Computer, and then I don't know what I'm supposed to do. Some instructions or a Help option would be nice. I then won by entering 4, 5, 6, 7, and the computer's moves didn't seem to take my moves into account. In fact, the computer only made 3 moves, probably not moving after I'd won.

You get extra points for commenting your code.

'x' is not a good name for a boolean variable. Give it a meaningful name.

The statement(s?) like

while ( x = true )

are incorrect. Think about it. The reason they don't result in an error (I think) is because the value of 'x' is irrelevant to the loop. Also,

while ( x )
or
while ( true )

would be sufficient as long as 'x' is a boolean.

There are too many magic numbers. Some are explained, but don't use them at all if you don't have to. Use variables like 'rows', 'columns', and 'squares' = 'rows' x 'columns' etc. . . .

Programmers are lazy (or seek to be efficient), so repeated code, like

if ( count != 4 )

is a signal that there's a better way.