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Java string manipulation x number of lines with y element

Easiest way to explain my problem is to give you an example. Lets say I have 2 values X and Y. I wan't to ask the user to enter X lines with Y elements and they should be only 0s and 1s and then enter that values in array.
Example
x=3 y=3
User input:
101
100
000
And then how to separate string to enter each value in different cell.
EDIT 1:
import java.util.Scanner;
public class RedVsGreen {
public static void main(String[] args) {
Scanner scanner=new Scanner(System.in);
int x,y;
String line;
String[] lineVector = new String[3];
while ( lineVector.length !=2 || (Integer.parseInt(lineVector[0]) >= 1000 || Integer.parseInt(lineVector[0]) <= 1)
|| (Integer.parseInt(lineVector[1]) <= 1 || Integer.parseInt(lineVector[1]) >= 1000)){
System.out.print("Please enter x and y, comma separated (more than 1 and less than 1000):");
//read x,y
line = scanner.nextLine();
//separate all values by comma
lineVector = line.split("\\s*,\\s*");
}
//parsing the values to Integer
x = Integer.parseInt(lineVector[0]);
y = Integer.parseInt(lineVector[1]);
for (i = 0 ; i < x; i++){
}
//
// int[][] field = new int[x][y];
// for (int row = 0; row < field.length; row++) {
// System.out.println("");
// for (int col = 0; col < field[row].length; col++) {
// field[row][col] = 9; //dummy value
// System.out.print(field[row][col] + " ");
// }
// }
//
}
}

Receiving x and y
while ( lineVector.length !=2 ...)
Your while condition is too complicated, a do while format matches this problem much better since you are going to get the values at least once, and the code is more readable.
Also you could have used x instead of Integer.parseInt(lineVector[0]) (same for y) instead of repeating the process, this would have shortened the condition.
String line;
String[] lineVector;
int x = -1, y = -1;
do {
System.out.print("Please enter x and y, comma separated (more than 1 and less than 1000):");
line = scanner.nextLine();
lineVector = line.split("\\s*,\\s*");
if(lineVector.length != 2)
continue;
x = Integer.parseInt(lineVector[0]);
y = Integer.parseInt(lineVector[1]);
} while (!((x > 1 && x < 1000 && y > 1 && y < 1000)));
First of all I removed the initial value of lineVector as it is unnecessary to initialize it in this case (you needed to do it because of it being present in your while condition).
I initialized x and y to -1 (Any number not in our range would work) in order to make sure the do-while condition is fulfilled until proper values are offered for both of the numbers.
Function to check binary values
Create a function to check if string values are binary.
public static boolean isBinary(String s) {
for(int i = 0; i < s.length(); ++i) {
char c = s.charAt(i);
if(c != '0' && c != '1')
return false;
}
return true;
}
Receive binaries
String[] binaries = new String[x];
System.out.println("Enter binaries with length " + y + " :");
//Get binaries
for(int i = 0; i < x; ++i) {
binaries[i] = scanner.nextLine();
while(!isBinary(binaries[i]) || binaries[i].length() != y) {
System.out.println("Invalid binary value. Re-enter new value:");
binaries[i] = scanner.nextLine();
}
}
Receive binary values and continue asking if invalid.
Filling the 2D array
int[][] field = new int[x][y];
for(int i = 0; i < x; ++i) {
System.out.println();
for(int j = 0; j < y; ++j) {
char c = binaries[i].charAt(j);
if(c == '0')
field[i][j] = 0;
else
field[i][j] = 1;
System.out.print(field[i][j] + " ");
}
}
Integer.parseInt is not necessary here as there are only two possible values (0 and 1)

Java: While Loop still running even when the condition is false

I'm fairly new at coding and in java in general but I'm hoping that I could get this figured out. I have a do while loop and inside that, I have a while statement if the incorrect value is input in the Scanner. However, when I run the code it always runs the while command once regardless of whether it is incorrect or correct and then runs the code correctly.
import java.util.Scanner;
public class Practice {
public static void main (String [] args) {
int x = 0;
int i = 0;
int n = 0;
String S1 = "";
Scanner user = new Scanner(System.in);
do
{
System.out.println("Enter an integer between 1 and 15: ");
x = user.nextInt();
while ( x < 1 || x > 15);
{
System.out.println("Incorrect integer. Must be between 1 and 15. Try again: ");
x = user.nextInt();
}
n = 1;
}
while (n != 1);
for (i = 1; i <= x; i++)
{
S1 = S1 + "X";
}
for (n = 1; n <= x; n++)
{
System.out.println(S1);
}
}
}
Thank you so much in advance.

Remove the extra ; from your while loop
Like this:
while ( x < 1 || x > 15){
System.out.println("Incorrect integer. Must be between 1 and 15. Try again: ");
x = user.nextInt();
}

while ( x < 1 || x > 15);
The Semi-Colon will terminate the logic and the control will pass to the next line always. Be careful while you code :D

Remove the extra semicolon in the while.
Also close the scanner object(user).
Check the updated code.
public class Practice {
public static void main(String[] args) {
int x = 0;
int i = 0;
int n = 0;
String S1 = "";
Scanner user = new Scanner(System.in);
do {
System.out.println("Enter an integer between 1 and 15: ");
x = user.nextInt();
while (x < 1 || x > 15)
{
System.out.println("Incorrect integer. Must be between 1 and 15. Try again: ");
x = user.nextInt();
}
n = 1;
} while (n != 1);
for (i = 1; i <= x; i++) {
S1 = S1 + "X";
}
for (n = 1; n <= x; n++) {
System.out.println(S1);
}
user.close();
}
}

Java output in lines of ten

I'm in a beginners java class and I have a quick question about the output statement on my array problem for week 5. So basically I have the core of the program down, but I'm supposed to output the result in lines of ten. I for some reason can not get it to work even with looking at similar posts on here. I'm a beginner and am pretty slow at putting 2 and 2 together when it comes to programming. Once I see it I have that ah-ha! moment and that's how this whole class has gone. I know I have to use the modulus, but in my trial and error I lost my way and have probably done more damage than good. Help would be appreciated.
Here is what I have and as you can tell I was trying something without modulus:
import java.util.*;
public class ArrayLoop
{
public static void main(String args[])
{
double alpha[] = new double[50];
*//Initialize the first 25 elements of the array (int i=0; i<25; i++)//*
for(int i = 0; i < 25; i++)
{
alpha[i]= i * i;
}
*//Initialize the last 25 elements of the array (i=25; i<50; i++)//*
for(int i = 25; i < 50; i++)
{
alpha[i]= 3 * i;
}
*//Print the element of the array*
System.out.println ( "The values are: " );
for (int i = 0; i < 50; i++)
System.out.println ( alpha[i] );
}
*//Print method to display the element of the array*
void print(double m_array[])
{
for(int i = 1; i < m_array.length; i++)
{
if(i % 10 == 0){;
System.out.println();
}else{
System.out.print(" ");
}
}
if (m_array.length % 10 != 0) {
System.out.println();
}
}
}

Um .. this isn't eloquent in the least but I tried to make the fewest changes to your existing code sample.
public class ArrayLoop {
public static void main(String args[]) {
double alpha[] = new double[50];
for (int i = 0; i < 25; i++) {
alpha[i] = i * i;
}
for (int i = 25; i < 50; i++) {
alpha[i] = 3 * i;
}
System.out.println("The values are: ");
for (int i = 0; i < 50; i++) {
System.out.print(alpha[i] + " ");
}
System.out.println();
System.out.println();
for (int i = 1; i < alpha.length; i++) {
if (i != 1 && i % 10 == 0) {
System.out.print(alpha[i - 1] + " ");
System.out.println();
} else {
System.out.print(alpha[i - 1] + " ");
}
}
System.out.print(alpha[49]);
}
}
Edit: A better condition would be ...
for (int i = 0; i < alpha.length; i++) {
if (i > 0 && i % 10 == 9) {
System.out.print(alpha[i] + " ");
System.out.println();
} else {
System.out.print(alpha[i] + " ");
}
}

You have to print the number first then decide whether to print space or newline by checking the modulus:
int arr[] = new int[50];
// Initialize array here
for (int i = 0; i < arr.length; i++) {
System.out.print(arr[i]);
if (i > 0 && (i + 1) % 10 == 0) {
System.out.println();
} else {
System.out.print(" ");
}
}

You have a couple of % 10 snippets in your code so I'm not entirely certain how that's "trying something without modulus" :-)
Having said that, modulus is exactly what you need, as per the following psuedo-code:
count = 0
for each item in list:
if count > 0 and (count % 10) == 0:
print end of line
print item
print end of line
In Java, you would use something like:
public class Test {
static public void main(String args[]) {
for (int i = 0; i < 24; i++) {
if ((i > 0) &&((i % 10) == 0)) {
System.out.println();
}
System.out.print ("" + i * 3 + " ");
}
System.out.println();
}
}
In other words, immediately before you print an item, check to see if it should be on the next line and, if so, output a newline before printing it.
Note that arrays in Java are zero based, so you need to start with an index of zero rather than one in your loops.
Now that's pretty close to what you have so you're on the right track but, for the life of me, I cannot see in your print() method where you actually print the item! That should be number one on your list of things to look into :-)
I urge you to try and work it out from the above text and samples but, if you're still having troubles after more than half an hour or so, the below code shows how I'd do it.
public class Test {
static void print (double m_array[]) {
for (int i = 0; i < m_array.length; i++) {
if ((i > 0) && ((i % 10) == 0))
System.out.println();
System.out.print (m_array[i] + " ");
}
System.out.println();
}
static public void main(String args[]) {
double[] x = new double[15];
for (int i = 0; i < x.length; i++)
x[i] = i * 3;
print (x);
}
}

In a Java Memory game, how do I trigger that 2 unknown has been discovered, and make them stay revealed for the rest of the game?

I'm currently doing a java memory game that makes the user guess duplicate letters by input the coordinate of either a 2x2, 4x4 or 6x6 square, which have 2 sets of repeating letters
ex. for 4x4 it would be
A B C D
E F G H
A B C D
E F G H
but randomized
If they guess correctly the letters would stay revealed, until all are found.
I have successfully randomized the square, and cover it with ( * ), and make them reveal based on the input coordinates
But I don't know how to make that once the 2 revealed letters are the same, the program will keep them revealed through out the game, until all duplicate letters are revealed.
The code right now (You can copy and paste whole thing below, all comments are commented out):
import java.util.Scanner;
import java.io.IOException;
public class a4{
// main method. DO NOT MODIFY
public static void main(String args[]) {
Scanner keyboard = new Scanner( System.in );
System.out.println("Welcome to Memory Game");
int board_side;
//this loop obtains the board size, or more specifically
// the length of the side of the board
do{
System.out.println("\n For 2x2 board game press 2"+
"\n For 4x4 board game press 4"+
"\n For 6x6 board game press 6");
board_side=keyboard.nextInt();
}while(board_side!=2 && board_side!=4 && board_side!=6);
char[][] board = createBoard(board_side);
// a call the the shuffle method
shuffleBoard(board);
// a call to the game playing method
playGame(board);
}
// The following method should shuffle the input 2D array caled board
public static void shuffleBoard(char[][] board)
{
// This creates a 1D array whose size is equal to the size of the board
int N = board.length*board.length;
char[] board1D = new char[N];
// Testing to see the printed square
for ( int i = 0; i < board.length; i++) {
for ( int j = 0; j < board[i].length; j++) {
System.out.print( board[i][j] + " " );
}
System.out.println();
}
System.out.println();
for (int i =0; i < board1D.length; i++) {
System.out.print(board1D[i] + " ");
}
System.out.println();
// Copy the elements of 2D array into that 1D array here
for (int m = 0; m < N; m++){
for (int i = 0; i < board.length; i++){
for (int j = 0; j < board.length; j++, m++){
board1D [m] = board[i][j];
}
}
}
// Shuffle 1D array
// Shuffle the array
for (int i = 0; i < N; i++) {
// Generate an index randomly
int index = (int)(Math.random() * N);
char temp = board1D[i];
board1D[i] = board1D[index];
board1D[index] = temp;
}
//Testing to see the 1D array
System.out.println();
for (int i =0; i < board1D.length; i++) {
System.out.print(board1D[i] + " ");
}
System.out.println();
//Copy shuffled 1D array back into 2D array, i.e., back to the board
for (int m = 0; m < N; m++){
for (int i = 0; i < board.length; i++){
for (int j = 0; j < board.length; j++, m++){
board[i][j] = board1D [m];
}
}
}
//Testing to print the shuffled square
for ( int i = 0; i < board.length; i++) {
for ( int j = 0; j < board[i].length; j++) {
System.out.print( board[i][j] + " " );
}
System.out.println();
}
System.out.println();
System.out.println();
}
// game playing method
public static void playGame(char[][] board)
{
Scanner keyboard = new Scanner( System.in );
// this createst a 2D array indicating what locations are paired, i.e., discovered
// at the begining none are, so default initializaiton to false is ok
boolean[][]discovered=new boolean[board.length][board[0].length];;
for ( int i = 0; i < board.length; i++) {
System.out.print(1 + i + " ");
for ( int j = 0; j < board[i].length; j++) {
System.out.print( "* " );
}
System.out.println();
}
System.out.print(" ");
for ( int x = 0; x < board.length; x++) {
System.out.print(1 + x + " ");
}
System.out.println();
System.out.println();
System.out.println("Enter a pair of undiscovered distinct locations on the board that you want revealed. i.e., a pair of integers in the range [1, 2]");
System.out.println();
int FirstLocationX;
int FirstLocationY;
int SecondLocationX;
int SecondLocationY;
do {
System.out.println("Enter the first location: ");
FirstLocationX=keyboard.nextInt();
FirstLocationY=keyboard.nextInt();
if (FirstLocationX > board.length && FirstLocationY > board.length){
System.out.println("The location is invalid. It is outside of the board. ");
}
} while(FirstLocationX > board.length && FirstLocationY > board.length);
System.out.println();
do {
System.out.println("Enter the second location: ");
SecondLocationX=keyboard.nextInt();
SecondLocationY=keyboard.nextInt();
if (SecondLocationX > board.length && SecondLocationY > board.length){
System.out.println("The location is invalid. It is outside of the board. ");
}
else if (SecondLocationX == FirstLocationX && SecondLocationY == FirstLocationY){
System.out.println("The location is invalid. The second location equal to the first. ");
}
} while(SecondLocationX > board.length && SecondLocationY > board.length && SecondLocationX == FirstLocationX && SecondLocationY == FirstLocationY);
//reveals the letters based on the coordinate user inputed
for ( int i = 0; i < board.length; i++) {
System.out.print(1 + i + " ");
for (int j = 0; j < board[i].length; j++) {
if (FirstLocationX == i+1 && FirstLocationY == j+1){
System.out.print( board[i][j] + " " );
}
else if (SecondLocationX == i+1 && SecondLocationY == j+1){
System.out.print( board[i][j] + " " );
}
/*This part is wrong, reveals the whole square instead of the found duplicates
else if (discovered[0][0] = true){
System.out.print( board[i][j] + " " );
}
else if (discovered[0][2] = true){
System.out.print( board[i][j] + " " );
}
*/
else {
System.out.print( "* " );
}
}
System.out.println();
}
System.out.print(" ");
for ( int x = 0; x < board.length; x++) {
System.out.print(1 + x + " ");
}
System.out.println();
System.out.println();
char[][] FirstInput = new char[FirstLocationX][FirstLocationY];
char[][] SecondInput = new char[SecondLocationX][SecondLocationY];
/*GETTING AN ERROR HERE when I try to trigger a duplicate letter found, since the array is shuffled I don't know how exactly, just testing with the first match right now (A and A), which suppose to be coordinate 0,0 and 0,2 in the non-sorted square matrix
*/
if (board[0][0] == FirstInput[FirstLocationX][FirstLocationY] && board[0][2] == SecondInput[SecondLocationX][SecondLocationY]){
discovered[0][0] = true;
discovered[0][2] = true;
}
waitForPlayer();
do {
playGame(board);
}while(discovered[0][0] == false && discovered[0][2] == false);
}
// createBoard method. DO NOT MODIFY!
/* this method, createBoard, creates the board filled with letters of alphabet,
where each letter appears exactly 2 times
e.g., for 4 x 4, the returned board would look like:
A B C D
E F G H
A B C D
E F G H */
public static char[][] createBoard(int side)
{
char[][] tmp = new char[side][side];
int letter_count=0;
for (int row = 0; row < tmp.length/2; row++){
for(int col = 0; col < tmp[row].length; col++)
{
tmp[row][col]=(char)('A'+letter_count);
tmp[row+tmp.length/2 ][col]=tmp[row][col];
letter_count++;
}
}
return tmp;
}
// waitForPlayer method. Do not modify!
public static void waitForPlayer()
{
System.out.print("Press enter to continue");
try {
System.in.read();
}
catch (IOException e){
System.out.println("Error reading from user");
}
}
}
The current part that is wrong is:
char[][] FirstInput = new char[FirstLocationX][FirstLocationY];
char[][] SecondInput = new char[SecondLocationX][SecondLocationY];
/*when I try to trigger a duplicate letter found, since the array is shuffled I don't know how exactly, just testing with the first match right now (A and A), which suppose to be coordinate 0,0 and 0,2 in the non-sorted square matrix
*/
if (board[0][0] == FirstInput[FirstLocationX][FirstLocationY] && board[0][2] == SecondInput[SecondLocationX][SecondLocationY]){
discovered[0][0] = true;
discovered[0][2] = true;
}
waitForPlayer();
do {
playGame(board);
}while(discovered[0][0] == false && discovered[0][2] == false);
}
and
else if (discovered[0][0] = true){
System.out.print( board[i][j] + " " );
}
else if (discovered[0][2] = true){
System.out.print( board[i][j] + " " );
}

I would suggest making each square as an object instead of having a mere char. That way you can control if they are revealed or not when you display then
Edit
Without objects, you can just create another array of bool that will track what is displayed. Whenever a pay is revealed, set the values inside that alternative board to true, then in your display function check if it is true before showing it

I would do the following:
Create an char[][] array in which the amount of * equals the input characters.
e.g.:
ABCD
DACB
'*****'
'****'
Get the coordinates which the user enters and compare them logically, if both characters are the same, then replace the corresponding * with the character.
e.g:
if the user input would be 0,0 for the first char and 1,1 for the second (both A)
then update the array to:
ABCD
DACB
A***
*A**
all the lines will be in one array but in the game you would print only the second two rows. The offset between the first two rows and the second two rows is the same, so it should be no problem to do that.

is there a better way to do this than my way?

I was asked the following question on a job interview. I was asked to do a form of 'padded printing' using an * character. Here is the code I provided as my answer (in java):
edit:
something like this: User input 3:
x x x x x
x * * * x
x * * * x
x * * * x
x x x x x>
public class asterisk {
public static void main (String args[]){
int input,ast;
Scanner scan = new Scanner(System.in);
System.out.println("Enter number: ");
input = scan.nextInt();
if(input>0) {
topBottom(input);
for(int x=1; x<=input; x++){
System.out.print("x ");
for( ast=1; ast<=input; ast++) {
System.out.print("* ");
}
System.out.print("x ");
System.out.println();
}
topBottom(input);
} else {
System.out.print("x ");
}
}
public static void topBottom(int input) {
for(int top = 1; top<=input+2; top++ ) {
System.out.print("x ");
}
System.out.println();
}
}
Is there a better more efficient way to do this aside from my way? Also, what did i do poorly in my code?
It would really mean a lot to me. I am now practicing commonly asked interview coding questions.

Your code is good but a few suggestions.
By convention, methods should start with a verb. The use of the topBottom function is questionable. I find it makes the code more confusing than anything. Consider readability as well as efficiency.
An approach like this is easier to read and doesn't include the extra method.
For n+2 chars in n+2 rows
for(int i=0; i<input+2; i++) {
for(int j=0; j<input+2; j++) {
Always print X for the first and last rows
if(i == 0 || i == input+1) {
System.out.print("X ");
}
For all other rows print X for the first and last character, otherwise print *
else {
if(j == 0 || j == input+1) {
System.out.print("X ");
} else {
System.out.print("* ");
}
}
Final Result:
for(int i=0; i<input+2; i++) {
for(int j=0; j<input+2; j++) {
if(i == 0 || i == input+1) {
System.out.print("X ");
} else {
if(j == 0 || j == input+1) {
System.out.print("X ");
} else {
System.out.print("* ");
}
}
}
System.out.println();
}

Minor changes, #Michael code , to print next line and print the char inside inner loop
// y = column
for(int y=0; y < input; y++){
// x = row
for(int x=0; x< input; x++){
nextChar = (x == 0 || y == 0 || (x+1) == input
|| (y+1) == input) ? BORDER : FILLING;
System.out.print(nextChar);
}
System.out.println();
}