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Creating a number rectangle in Java using a nested for loop with one number input

I'm new to Java and have an assignment that requires me to create a rectangle of numbers where the numbers start from the 'user input' number and reduce to 1 in the middle (See example).
I've created a very simplified code that can do it, but I would have to create an 'else if' for each number up to the 'user input' number.
Obviously, there is a way to repeat the code using some variable, but I can't seem to figure out how to do it. Can I get some help? Here is the code I am at right now:
import java.util.Scanner;
public class Assign {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
System.out.println("Select rectangle size:");
int user = scan.nextInt();
for (int row = 1; row <= ((user*2)-1); row++) {
for (int col = 1; col <= ((user*2)-1); col ++) {
if ((row == 1) || (col == 1) || (row == (user*2)-1) || (col == (user*2)-1)) {
System.out.printf("%2d",user);
}else if ((col == (2)) || col == (user*2)-(2) || row == 2 || row == (user*2)-(2)) {
System.out.printf("%2d",user - (1));
}else if ((col == (3)) || col == (user*2)-(3) || row == 3 || row == (user*2)-(3)) {
System.out.printf("%2d",user - (2));
}else if ((col == (4)) || col == (user*2)-(4) || row == 4 || row == (user*2)-(4)) {
System.out.printf("%2d",user - (3));
}else if ((col == (5)) || col == (user*2)-(5) || row == 5 || row == (user*2)-(5)) {
System.out.printf("%2d",user - (4));
}
}
System.out.println();
}
input.close();
}
}

I have a solution for this problem. I hope It can help you.
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("Please select your max number:");
int userChoice = input.nextInt();
int end = userChoice * 2 - 1;
int decrement = 0;
int increment = 0;
for (int i = 0; i < end; i++) {
for (int j = 0; j < end; j++) {
if(end - i - 1 < j) {
increment++;
}
System.out.print(userChoice - decrement + increment);
if(decrement < i) {
decrement++;
}
}
decrement = 0;
increment = 0;
System.out.println();
}
input.close();
}

my do-while loop seems to be running forever even though i change the value of the condition

boolean onGoing = true;
do {
String p1 = "playing";
while (p1.equals("playing")) {
System.out.println("Player 1, enter hit row/column:");
int a = sc.nextInt();
int b = sc.nextInt();
if (a >= 0 && a < 5 && b >= 0 && b < 5) {
if (history1[a][b] == '-') {
p1 += " no more";
if (board2[a][b] == '#') {
history1[a][b] = 'X';
board2[a][b] = 'X';
String status = check(board2);
if (status.equals("win")) {
System.out.println("PLAYER 1 WINS! YOU SUNK ALL OF YOUR OPPONENT'S SHIPS!");
onGoing = false;
printBattleShip(board1);
printBattleShip(board2);
break;
} else {
System.out.println("PLAYER 1 HIT PLAYER 2's SHIP!");
}
} else if (board2[a][b] == '-') {
System.out.println("PLAYER 1 MISSED!");
history1[a][b] = 'O';
board2[a][b] = 'O';
}
} else {
System.out.println("You already fired on this spot. Choose different coordinates.");
}
} else {
System.out.println("Invalid coordinates. Choose different coordinates.");
}
}
String p2 = "playing";
while (p2.equals("playing")) {
System.out.println("Player 2, enter hit row/column:");
int c = sc.nextInt();
int d = sc.nextInt();
if (c >= 0 && c < 5 && d >= 0 && d < 5) {
if (history2[c][d] == '-') {
p2 += " no more";
if (board1[c][d] == '#') {
history2[c][d] = 'X';
board1[c][d] = 'X';
String status = check(board1);
if (status.equals("win")) {
System.out.println("PLAYER 2 WINS! YOU SUNK ALL OF YOUR OPPONENT'S SHIPS!");
onGoing = false;
printBattleShip(board2);
printBattleShip(board1);
break;
} else {
System.out.println("PLAYER 2 HIT PLAYER 1's SHIP!");
}
} else if (board1[c][d] == '-') {
history2[c][d] = 'O';
board1[c][d] = 'O';
System.out.println("PLAYER 2 MISSED!");
}
} else {
System.out.println("You already fired on this spot. Choose different coordinates.");
}
} else {
System.out.println("Invalid coordinates. Choose different coordinates.");
}
}
} while (onGoing);
private static String check(char[][] arr1) {
int sum = 0;
for (int i = 0; i < arr1.length; i++) {
for (int j = 0; j < arr1.length; j++) {
if (arr1[i][j] == '#') {
sum += 1;
}
}
}
if (sum == 0) {
return "win";
} else {
return "keep playing";
}
}
// I declared and initialized a boolean variable called ongoing before a do-while loop. Then I create a while loop inside the do while loop. And inside the while loop, there are a series of conditional statement. Eventually, I changed the value of the boolean variable and feed it back to the while statement, letting it evaluate it. But it doesn't seem to change the value. Is it because the scope of the variable? How can I fix it?
edit: check method added

Nested loop infinitely looping after random interval?

I am programming a connect 4 game using Java for an assignment. However, whenever player 2 makes a move about 5 moves in, the player 2 loop will infinitely loop. There is some sort of logic error that I cannot find, and it is frustrating. What is the logic error, and what is a good way to avoid future mistakes of the same vain?
I have tried changing the variables for the do > while loop where player 1 and player two attempt their moves. However that has no affect on it.
import java.util.Arrays;
public class Lab6Shell {
public static void main(String args[]) {
// variables
Scanner input = new Scanner(System.in);
char[][] board = new char[7][8];
boolean finished = false;
boolean gameOver = false;
int width = 7;
int height = 8;
char currentPlayer = 'X';
int numMoves = 0;
int bottom_row = width - 1;
// loop until user wants to stop
for (int row = 0; row < board.length; row++) {
java.util.Arrays.fill(board[row], 0, board[row].length, '*');
}
do {
// display the board
DisplayBoard(board);
// loop until this game is over
do {
// get the next move for the current player
int columnChosen = 0;
do {
if (currentPlayer == 'X') {
int counter = 1;
System.out.println("Player 1 turn");
System.out.println("Enter the column you want to place your piece.");
columnChosen = input.nextInt();
input.nextLine();
while (true) {
if (columnChosen > width) {
System.out.println("That's not a valid column");
break;
}
if ((board[bottom_row][columnChosen] == '*')) {
board[bottom_row][columnChosen] = 'X';
break;
} else if ((board[bottom_row][columnChosen] == 'X')
|| (board[bottom_row][columnChosen] == 'O')) {
if (board[bottom_row - counter][columnChosen] == '*') { // puts X if blank
board[bottom_row - counter][columnChosen] = 'X';
break;
}
counter += 1;
if (counter == width) {
System.out.println("That column is full");
break;
}
}
}
}
if (currentPlayer == 'O') {
int counter = 1;
System.out.println("Player 2's turn");
System.out.println("Enter the column you want to place your piece.");
columnChosen = input.nextInt();
input.nextLine();
while (true) {
if (columnChosen > width) {
System.out.println("That's not a valid column");
break;
}
if ((board[bottom_row][columnChosen] == '*')) {
board[bottom_row][columnChosen] = 'O';
break;
} else if ((board[bottom_row][columnChosen] == 'X')
|| (board[bottom_row][columnChosen] == 'O')) {
if (board[bottom_row - counter][columnChosen] == '*') { // puts O
board[bottom_row - counter][columnChosen] = 'O';
break;
}
counter += 1;
if (counter == width) {
System.out.println("That column is full");
break;
}
}
}
}
} while (columnChosen < 0 || columnChosen > 8 || board[1][columnChosen] != '*');
// place piece
// increment number of moves
numMoves++;
// display the board
DisplayBoard(board);
// check for win
if (checkWin(board)) {
// if winner, display congratulations and set gameOver true
System.out.println("Congratulations! You won!");
gameOver = true;
} else if (numMoves == 42) {
// if tie, display result and set gameOver true
DisplayBoard(board);
System.out.println("Tie Game! Game over");
gameOver = true;
} else if (checkWin(board) == false) {
if (currentPlayer == ('X')) {
currentPlayer = ('O');
} else {
currentPlayer = ('X');
}
}
} while (!gameOver);
// ask if user wants to play again, set finished accordingly
System.out.println("Would you like to play again?");
input.nextLine();
String decision = input.nextLine();
if (decision.toLowerCase().equals("yes")) {
finished = false;
}
else if (decision.toLowerCase().equals("no")) {
finished = true;
}
} while (finished == false);
}
// this method displays the board passed in
public static void DisplayBoard(char[][] board) {
for (int i = 0; i < board.length; i++) {
System.out.print("|");
for (int j = 0; j < board[i].length; j++) {
System.out.print(" " + board[i][j] + "|");
}
System.out.println("");
}
}
public static boolean checkWin(char[][] board) {
final int HEIGHT = board.length;
final int WIDTH = board[0].length;
final int EMPTY_SLOT = '*';
for (int r = 0; r < HEIGHT; r++) { // iterate rows, bottom to top
for (int c = 0; c < WIDTH; c++) { // iterate columns, left to right
char player = board[r][c];
if (player == EMPTY_SLOT)
continue; // don't check empty slots
if (c + 3 < WIDTH && player == board[r][c + 1] && // look right
player == board[r][c + 2] && player == board[r][c + 3])
return true;
if (r + 3 < HEIGHT) {
if (player == board[r + 1][c] && // look up
player == board[r + 2][c] && player == board[r + 3][c])
return true;
if (c + 3 < WIDTH && player == board[r + 1][c + 1] && // look up & right
player == board[r + 2][c + 2] && player == board[r + 3][c + 3])
return true;
if (c - 3 >= 0 && player == board[r + 1][c - 1] && // look up & left
player == board[r + 2][c - 2] && player == board[r + 3][c - 3])
return true;
}
}
}
return false; // no winner found
}
}
The expected result is that each player will play a piece until four of the same piece are in a row. Then the first to reach four in a row is declared the winner, and the game ends. However, once the game gets in about 5 loops, the player 2 loop infinitely loops until a column is full, and does not print out the board.

Your infinite loop is caused by checking the condition board[1][columnChosen] != '*' in your do ... while loop. The program will continue to ask the current user for a new move as long as the second to top row of the selected column is occupied.
Replace:
do
{
...
} while (columnChosen < 0 || columnChosen > 8 || board[1][columnChosen] != '*');
With:
do
{
...
} while (columnChosen < 0 || columnChosen > 8)
This should get you to a point where you can tackle the remaining issues.

Assistance with Tic Tac Toe program

I've been working on for awhile but i can't seem to fix it and get it to wrong correctly. It tells me where the exception is but I don't see any problems.
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 3
at TicTacToe.displayWinner(TicTacToe.java:243)
at TicTacToe.playerMove(TicTacToe.java:151)
at TicTacToe.playGame(TicTacToe.java:303)
at TicTacToeTester.main(TicTacToeTester.java:20)
Java Result: 1
import java.util.Scanner; //Used for player's input in game
public class TicTacToe
{
//instance variables
private char[][] board; //Tic Tac Toe Board, 2d array
private boolean xTurn; // true when X's turn, false if O's turn
private Scanner input; // Scanner for reading input from keyboard
//Constants for creation of gameboard
public final int ROWS = 3; //total rows
public final int COLS = 3; //total columns
public final int WIN = 3; //amount needed to win
public TicTacToe()
{
//creates the board
board = new char[ROWS][COLS];
for(int r = 0; r < ROWS; r++)
{
for(int c = 0; c < COLS; c++)
{
board[r][c] = ' ';
}
}
//X's turn when game starts
xTurn = true;
//creates our input object for the turn player
input = new Scanner(System.in);
}
//shows game board
public void displayBoard()
{
int colNum = 0; //number of columns
int rowNum = 0; //number of rows
//creates column labels
System.out.println(" \n");
System.out.println(" Columns ");
for (int num = 0; num < COLS; num++)
{
System.out.print(" " + colNum);
colNum++;
}
//creates vertical columns and spaces between each spot
System.out.println(" \n");
for (int row = 0; row < ROWS; row++)
{
//numbers rows
System.out.print(" " + rowNum + " ");
rowNum++;
for (int col = 0; col < COLS; ++col)
{
System.out.print(board[row][col]); // print each of the cells
if (col != COLS - 1)
{
System.out.print(" | "); // print vertical partition
}
}
System.out.println();
//creates seperation of rows
if (row != ROWS - 1)
{
System.out.println(" ------------"); // print horizontal
partition
}
}
//labels row
System.out.println("Rows \n");
}
//displays turn player
public void displayTurn()
{
if (xTurn)
{
System.out.println("X's Turn");
}
else
{
System.out.println("O's Turn");
}
}
//allows you to make move
public boolean playerMove()
{
boolean invalid = true;
int row = 0;
int column = 0;
while(invalid)
{
System.out.println("Which row (first) then column (second)
would you like to \n"
+ "play this turn? Enter 2 numbers between 0-2 as \n"
+ "displayed on the board, seperated by a space to
\n"
+ "choose your position.");
row = input.nextInt();
column = input.nextInt();
//checks if spot is filled
if (row >= 0 && row <= ROWS - 1 &&
column >= 0 && column <= COLS - 1)
{
if (board[row][column] != ' ')
{
System.out.println("Spot is taken \n");
}
else
{
invalid = false;
}
}
else
{
System.out.println("Invalid position");
}
//fills spot if not taken
if (xTurn)
{
board[row][column] = 'X';
}
else
{
board[row][column] = 'O';
}
}
return displayWinner(row,column);
}
public boolean displayWinner(int lastR, int lastC)
{
boolean winner = false;
int letter = board[lastR][lastC];
//checks row for win
int spotsFilled = 0;
for (int c = 0; c < COLS; c++)
{
if(board[lastR][c] == letter)
{
spotsFilled++;
}
}
if (spotsFilled == WIN)
{
winner = true;
if (xTurn)
{
System.out.println("X won");
displayBoard();
}
else
{
System.out.println("O won");
displayBoard();
}
}
//checks columns for win
spotsFilled = 0;
for (int r = 0; r < ROWS; r++)
{
if(board[r][lastC] == letter)
{
spotsFilled++;
}
}
if (spotsFilled == WIN)
{
winner = true;
if (xTurn)
{
System.out.println("X won");
displayBoard();
}
else
{
System.out.println("O won");
displayBoard();
}
}
//checks diagonals for win
spotsFilled = 0;
for (int i = 0; i < WIN; i++)
{
if(board[i][i] == letter)
{
spotsFilled++;
}
}
if(spotsFilled == WIN)
{
winner = true;
if (xTurn)
{
System.out.println("X won");
displayBoard();
}
else
{
System.out.println("O won");
displayBoard();
}
}
//checks other diagonal
spotsFilled = 0;
for(int i = 0; i < WIN; i++)
{
if(board[i][COLS-i] == letter)
{
spotsFilled++;
}
}
if(spotsFilled == WIN)
{
winner = true;
if (xTurn)
{
System.out.println("X won");
displayBoard();
}
else
{
System.out.println("O won");
displayBoard();
}
}
return winner;
}
//checks if board is full
public boolean fullBoard()
{
int filledSpots = 0;
for(int r = 0; r < ROWS; r++)
{
for (int c = 0; c < COLS; c++)
{
if (board[r][c] == 'X' || board[r][c] == 'O')
{
filledSpots++;
}
}
}
return filledSpots == ROWS*COLS;
}
//plays game
public void playGame()
{
boolean finish = true;
System.out.println("Are your ready to start?");
System.out.println("1 for Yes or 0 for No? : ");
int choice = input.nextInt();
if (choice == 1)
{
while (finish)
{
displayBoard();
displayTurn();
if (playerMove())
{
displayBoard();
}
else if (fullBoard())
{
displayBoard();
System.out.println("Draw");
}
else
{
xTurn=!xTurn;
}
}
}
}
}
my tester
public class TicTacToeTester {
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
TicTacToe tictactoe = new TicTacToe();
tictactoe.playGame();
}
}

Your Player Move method has an issue take a look at this if you notice you have commented saying "// fills spot when not taken" but you misplaced the while loop bracket and included move part inside it so it threw that exception, just close the while loop bracket before moving as follows (also follow #oblivion Creations Answer these are the two issues with your code) :-
public boolean playerMove()
{
boolean invalid = true;
int row = 0;
int column = 0;
while (invalid)
{
System.out.println("Which row (first) then column (second)" + "would you like to \n"
+ "play this turn? Enter 2 numbers between 0-2 as \n"
+ "displayed on the board, seperated by a space to" + "\n" + "choose your position.");
row = input.nextInt();
column = input.nextInt();
// checks if spot is filled
if (row >= 0 && row <= ROWS - 1 && column >= 0 && column <= COLS - 1)
{
if (board[row][column] != ' ')
{
System.out.println("Spot is taken \n");
}
else
{
invalid = false;
}
}
else
{
System.out.println("Invalid position");
}
} // close while loop here
// fills spot if not taken
if (xTurn)
{
board[row][column] = 'X';
}
else
{
board[row][column] = 'O';
}
return displayWinner(row, column);
}

The reason you are getting your exception is this section of code inside your displayWinner method:
//checks other diagonal
spotsFilled = 0;
for(int i = 0; i < WIN; i++)
{
if(board[i][COLS-i] == letter)
{
spotsFilled++;
}
}
When i = 0 then COLS-i will be 3. This is outside the bounds of your array.
There are multiple ways to solve this, one would be to increase i by 1 during comparison.
//checks other diagonal
spotsFilled = 0;
for(int i = 0; i < WIN; i++)
{
if(board[i][COLS-(i+1)] == letter)
{
spotsFilled++;
}
}
Edit: also make sure you check out Null Saints answer, as it will cause you headaches later if you don't address it now.

Tic Tac Toe java draw game

So I did a Tic Tac Toe assignment for my class. I have successfully created a simple Tic Tac Toe program but somehow the method to check for draw sometimes doesn't come out right. If everything is filled but there's no winner, then it's a draw. But if everything else is filled except for row 0 column 1, it will still show "draw" even if that box is still blank. If you don't get what I mean, just try filling out everything but the middle box on the top row but don't win, it will say "draw" even though that last box is not filled. What did I do wrong in my code???? Here's the driver:
import javax.swing.JOptionPane;
public class TwoDimensionalArray_Driverr
{
public static void main(String[]args)
{
char player = 'o';
TwoDimensionalArrayy game = new TwoDimensionalArrayy();
while (game.checkGame() == "PLAY")
{
if (player == 'o') player = 'x';
else player = 'o';
System.out.println(game);
String input = JOptionPane.showInputDialog("Enter Position of Row for player "+ player +" or press Cancel to exit");
if (input == null)
System.exit(0);
int row = Integer.parseInt(input);
input = JOptionPane.showInputDialog("Enter Position of Column for player " + player);
int column = Integer.parseInt(input);
game.set(row,column,player);
game.isDraw();
game.hasWon(row,column,player);
game.checkGame();
System.out.println(game.checkGame());
}
if (game.checkGame()=="DRAW"){
System.out.println(game);
System.out.println("It's a draw.");
}
else {
System.out.println(game);
System.out.println(player + " has won.");}
}
}
And here is the Object:
public class TwoDimensionalArrayy
{
private String currentState = "GO";
private char[][] board;
private static final int ROWS = 3;
private static final int COLUMNS = 3;
public TwoDimensionalArrayy(){
board = new char[ROWS][COLUMNS];
for(int i=0;i<ROWS;i++) //always do ROWS first!!!!
for(int j = 0;j<COLUMNS;j++)
board[i][j]=' ';
}
public void set(int i, int j, char player)
{
if(board[i][j] != ' ' )
throw new IllegalArgumentException("Position Occupied");
board[i][j] = player;
}
public String toString()
{
System.out.println("This is the board. 3x3");
System.out.println("Position start # row[0]col[0],row[0]col[1],row[0]col[2]");
String dString= "";
for (int row = 0; row<ROWS; row++)
{
if (COLUMNS>0)
dString += board[row][0];
for (int col = 1; col<COLUMNS; col++)
{
dString+= "|" + board[row][col];
} //end 2nd for
dString += "\n";
}//end first for
return dString;
}
public String checkGame(){
if (currentState=="Win"){
return "END";}
else if (currentState=="Draw"){
return "DRAW";}
else return "PLAY";
}
public void hasWon(int i,int j,char player){
if (board[i][0] == player // 3-in-the-row
&& board[i][1] == player
&& board[i][2] == player
|| board[0][j] == player // 3-in-the-column
&& board[1][j] == player
&& board[2][j] == player
|| i == j // 3-in-the-diagonal
&& board[0][0] == player
&& board[1][1] == player
&& board[2][2] == player
|| i + j == 2 // 3-in-the-opposite-diagonal
&& board[0][2] == player
&& board[1][1] == player
&& board[2][0] == player)
currentState = "Win";
}
public void isDraw(){
for ( int row = 0; row < ROWS; row++) {
for (int col = 0; col < COLUMNS; col++) {
if (board[row][col] == ' ') {
currentState = "Play";
break;
}
else {currentState = "Draw";} // no empty cell, it's a draw}
}
}
}
}

public void isDraw(){
for ( int row = 0; row < ROWS; row++) {
for (int col = 0; col < COLUMNS; col++) {
if (board[row][col] == ' ') {
currentState = "Play";
break;
} else {
currentState = "Draw"; // no empty cell, it's a draw
}
}
}
}
The break here will escape the inner for loop, but not the outer one. Essentially isDraw only considers the last row. You should try using return instead.