We Keep Coding

Calculate dots on cuboid's grid

I have an issue with my math skills here. So I need to calculate the positions (x, y, z) of a specific amount of dots per aixs. For example take this image
final double gapX = lengthX / dotsPerXAxis;
final double gapY = lengthY / dotsPerYAxis;
final double gapZ = lengthZ / dotsPerZAxis;
for (BlockFace blockFace : BlockHandler.DIRECT_RELATIVES) {
final DecimalVector3D minCorner = new DecimalVector3D(
blockFace.getModX(),
blockFace.getModY(),
blockFace.getModZ()
);
for (int x = 0; x < dotsPerXAxis || x == 0; x++) {
for (int y = 0; y < dotsPerYAxis; y++) {
for (int z = 0; z < dotsPerZAxis; z++) {
}
}
}
My question now is: how can I iterate over all the dots except those that are inside the cuboid and calculate their position and put them in an ImmutableList?

You need to treat point if at least one coordinate of it is zero or dotsPerZAxis.
So set flags - if X-coordinate lies on face, if Y-coordinate lies on face. If both flags are not set - get only the first and the last Z-coordinates, otherwise walk through all Z-coordinates.
Unchecked Java:
for (int x = 0; x < dotsPerXAxis; x++) {
bool atX = (x == 0) || (x == dotsPerXAxis - 1);
for (int y = 0; y < dotsPerYAxis; y++) {
bool atY = (y == 0) || (y == dotsPerYAxis - 1);
int zstep = (atX || atY)? 1: dotsPerZAxis - 1;
for (int z = 0; z < dotsPerZAxis; z+=zstep) {
treat(x,y,z)
}
}
}
Ideone Python working code as proof-of-concept gives n^3 - (n-2)^3 points (26 surface points for n=3, 56 for n=4, 98 for n=5)

Based on the help of MBo I figured this out
for (BlockFace blockFace : BlockHandler.DIRECT_RELATIVES) {
for (int x = 0; x < dotsPerXAxis || x == 0 || x == dotsPerXAxis - 1; x++) {
for (int y = 0; y < dotsPerXAxis || y == 0 || y == dotsPerYAxis - 1; y++) {
for (int z = 0; z < dotsPerXAxis || z == 0;
z += (y == 0 || y == dotsPerYAxis - 1) || (x == 0 || x == dotsPerXAxis - 1) ? 1 :
dotsPerZAxis - 1) {
results.add(new DecimalVector3D(
x,
y,
z
));
}
}
}
}

(Java) How can I store my x and y values to use them outside of for loops?

I'm coding Conway's Game of Life on Processing 3 and I want to store x and y so that the squares don't change right away, but I don't know how to store it to use later. Any help is appreciated!
void keyPressed() {
for (int x = 0; x < 30; x++) {
for (int y = 0; y < 30; y++) {
int numNeighbours = numNeighbours(x,y);
if (cells[x][y] == true) {
if (numNeighbours > 3 || numNeighbours <= 1) { //underpopulation or overpopulation
}
}
else if (cells[x][y] == false) {
if (numNeighbours == 3) {
}
}
}
}
}

Based on my understanding of your code (and the Game of Life), you don't need to store x and y. What you actually need to do is to store the (x, y) pairs where the cell changes state.
You could do this by creating pairs and adding them to lists.
But a another idea is to use a second array representing the next generation of the game and put all of the new values there; e.g.
for (int x = 0; x < 30; x++) {
for (int y = 0; y < 30; y++) {
int numNeighbours = numNeighbours(x,y);
if (cells[x][y] == true) {
if (numNeighbours > 3 || numNeighbours <= 1) {
cellsNext[x][y] = false;
} else {
cellsNext[x][y] = true;
}
}
else if (cells[x][y] == false) {
if (numNeighbours == 3) {
cellsNext[x][y] = true;
} else {
cellsNext[x][y] = false;
}
}
}
}
Note: that could be simplified / written better, but I have written it as above so that you can see clearly what I have done.

Programming a battleships ship placing algorithm(java)

So im programming a battleships game, and im trying to place ships on a board. I can get it to place the ship going left and going down from the starting point but cant get it going down or left. I understand my method overall is in-effeicient.
public static int[][] SetUserBoard(int[][] board) {
int x;
int y;
y = 0;
for (int z = 0; z < 10; z++) {
String gridv;
gridv = "";
int direction;
System.out.println("Set the Position for Ship no. " + (z+1));
Scanner s1 = new Scanner(System.in);
System.out.println("Enter the grid column(A-H):");
gridv = s1.nextLine();
if (gridv.equals("A")) {
y = 0;
}
if (gridv.equals("B")) {
y = 1;
}
if (gridv.equals("C")) {
y = 2;
}
if (gridv.equals("D")) {
y = 3;
}
if (gridv.equals("E")) {
y = 4;
}
if (gridv.equals("F")) {
y = 5;
}
if (gridv.equals("G")) {
y = 6;
}
if (gridv.equals("H")) {
y = 7;
}
System.out.println("Enter the y co=ordinate: ");
x = s1.nextInt();
x -= 1;
System.out.println("Enter the direction of the ship 0-3(0=down,1=right,2=up,3=left): ");
direction = s1.nextInt();
if(z == 0) { //placing 4 unit ship in first increment
if(direction == 0 && x < 5){ //vertical placement - down
for(int i=0; i < 4; i++) {
board[x][y] = 0;
x += 1;
}
}
if(direction == 1 && y < 5) { //horizontal placement - right
for(int i=0; i < 4; i++) {
board[x][y] = 0;
y += 1;
}
}
if(direction == 2 && x > 3 ) { //vertical placement - up
for(int i=0; i < 4; i++) {
board[x][y] = 0;
x -= 1;
}
}
if(direction == 3 && y > 3) { //horizontal placement - left
for(int i=0; i < 4; i++) {
board[x][y] = 0;
y -= 1;
}
}
}
...if(z > 0 && z < 3) { //placing 3 unit ships in 2nd and 3rd increment....
return board;
}
if you ignore the bottom part, and focus on the if z=0 part as that's which part i'm using to test this with my most updated try. Originally I had an indexing error which I managed to solve but now all the program does is run as usual except when moving onto the next one the board isn't updated and is still empty. So im stumped as to what logic to use for up/left.

For diagonal changes, you need to alter both i and j as you traverse the ship. For instance:
UP_LEFT = 4
...
ship_len = 4
...
if(direction == UP_LEFT &&
y > ship_len-1 &&
x > ship_len-1) { // SE-NW placement
for(int i=0; i < ship_len; i++) {
board[x][y] = 0;
y -= 1;
x -= 1;
}
}

im having trouble in while loop

I'm making a simple "Whack a mole" game in Java. For simplicity I have created a 10*10 box and placed 10 moles in random boxes. I want to exit the game when the user spent his 50 inputs or found all 10 moles, but there seems to be a problem in terminating the while loop even when the user attempts specified inputs.
Is it Instance variable scope problem? Why it is not working?
public class WhackAMole {
int score = 0, molesLeft = 10, attempts;
char[][] moleGrid = new char[10][10];
int numAttempts, gridDimension;
public WhackAMole(int numAttempts, int gridDimension) {
// TODO Auto-generated constructor stub
this.numAttempts = numAttempts;
this.gridDimension = gridDimension;
}
boolean place(int x, int y) {
return (x == 2 && y == 5)
|| (x == 1 && y == 3)
|| (x == 8 && y == 4)
|| (x == 5 && y == 10)
|| (x == 6 && y == 9)
|| (x == 10 && y == 7)
|| (x == 3 && y == 7)
|| (x == 2 && y == 9)
|| (x == 4 && y == 8)
|| (x == 9 && y == 5);
}
void whack(int x, int y) {
if (place(x, y)) {
if (moleGrid[x - 1][y - 1] == 'W') {
System.out.println("Already attempted! \'try other co-ordinates\' \n");
} else {
moleGrid[x - 1][y - 1] = 'W';
this.score ++;
this.molesLeft --;
}
}
}
void printGridToUser() {
System.out.println("your score is " + score + " and " + molesLeft + " moles are left. \n");
System.out.println("input x = -1 and y = -1 to quit the game! \n");
for(int i = 0; i < 10; i++){
for(int j = 0; j < 10; j++){
System.out.print(" " + moleGrid[i][j] + " ");
}
System.out.println("\n");
}
}
void printGrid() {
for(int i = 0; i < 10; i++){
for(int j = 0; j < 10; j++){
this.moleGrid[i][j] = '*';
}
}
}
public static void main(String[] args) {
WhackAMole game;
System.out.println("Lets play the Whack A Mole!\n");
game = new WhackAMole(50, 100);
game.printGrid();
game.printGridToUser();
Scanner scanner = new Scanner(System.in);
while ((game.numAttempts > 0) || (game.molesLeft > 0)) {
System.out.println("Enter box co-ordinate\n");
System.out.println("x co-ordinate: \n");
int x = scanner.nextInt();
System.out.println("y co-ordinate: \n");
int y = scanner.nextInt();
if (x == -1 && y == -1) {
break;
} else if ((x < 1 || y < 1) || (x > 10 || y > 10)) {
System.out.println("please enter values of x and y greater than 0 and less than 11! \n");
} else {
game.whack(x, y);
game.numAttempts--;
game.gridDimension--;
System.out.println("you can have upto " + game.numAttempts + " out of " + game.gridDimension + " boxes \n");
game.printGridToUser();
}
}
for (int i = 0; i < 10; i++) {
for (int j = 0; j < 10; j++) {
if (game.place(i+1, j+1) && game.moleGrid[i][j] != 'W'){
game.moleGrid[i][j] = 'M';
}
}
}
game.printGridToUser();
scanner.close();
System.out.println("game over!!!\n");
}
}

Your while loop is not ending because you are using || in your while loop. The || is making your loop run until the attempts allowed i.e. 50 and the right guessing i.e. finding moles correct both are met. So even when a gamer has finished his allowed attempts and hasn't guessed all the right moles positions, the loop will not end
The simple solution would be to replace || with &&
while ((game.numAttempts > 0) && (game.molesLeft > 0))
And avoid using fixed numbers i.e. 10 in your for loops instead use
for (int i = 0; i < game.gridDimension; i++) {
for (int j = 0; j < game.gridDimension; j++) {
I hope it helps

Your loop is using an or for the test function. This means both condition mist be false in order for it to stop. In your case. How its written you must exhaust the numtries and have no moles left.
Change to use && vs ||.

Java several conditions with the help of for loop

I wonder if it is possible to have minimal code for this:
for (int x = 1; x < 10; x++){
/*I want to replace this condition with (x%number == 0)
instead of writing out condition for every number, but
it did not work with for (int number = 1; number <= 3; number++)
in (x%number == 0), as it prints out every x and number
*/
if ((x%1) == 0 && (x%2) == 0 & (x%3) == 0){
System.out.println(success!);
}
}

I think
x % a == 0 && x % b == 0 && x % c == 0
is equalent to
x % (a * b * c) == 0
UPDATE
Multiplication is incorrect, you need to use LCM: x % lcm(a, b, c)

Have a look :
for (int x = 1; x < 10; x++){
boolean flag = false;
for(int num = 1; num <= 3; num++){
if ((x%num) == 0 ){
flag = true;
}else{
flag = false;
break;
}
}
if(flag){
System.out.println(x + " success!");
}
}
OUTPUT :
6 success!
I know the code is looking a little horrified but will work for any value of x and num

This is what you'd need to make a comp sci professor happy:
for (int x = 1; x < 10; x++){
boolean success = true;
for (int number = 1; number <= 3; number++) {
if ((x % number) != 0) {
success = false;
}
}
if (success) {
System.out.println("success!");
}
}
although note: (x % 1) is always 0.
This is what you'd need to make me happy, according to my rule of "avoid nested loops":
for (int x = 1; x < 10; x++) {
if (testNumber(x))
System.out.println(x + " success!");
}
}
private static boolean testNumber(int x) {
for (int number = 1; number <= 3; number++) {
if ((x % number) != 0) {
return false;
}
}
return true;
}