I would like some help understanding why my program is printing a grid of
....................
....................
....................
....................
....................
...............OOOOO
OOOOOOOOOOOOO.......
....................
....................
....................
The correct output would be so:
....................
....................
....................
....................
....................
....................
....................
.............O.O....
..............OO....
..............O.....
The way I wrote it is to create a copy of the old state and manipulate it using the rules of the game. After I check every cell, I store count of the number of neighbors alive for that cell. IF the count is greater than 3 or less than two, the cell will die.
If a cell has a count of 2 or 3 neighbors, it remains alive.
If a dead cell has a count of 3, it becomes alive.
These rules are directly applied to the copy version instead of the old and then print the copy.
I've tried using a debugger but I'm still unsure of how to use it properly. I haven't notice any red flags as of yet.
Here's my code:
#include <iostream>
#include <vector>
using std::vector;
using std::cout;
vector<vector<bool> > world = {
{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0},
{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0},
{0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,0,0,0,0},
{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}
};
void generate(const vector<vector<bool> >&g,vector<vector<bool> >&newworld)
{
int count = 0;
newworld = g;
for(size_t i = 0; i < g.size();i++) {
for(size_t j = 0; j < g[i].size();j++) {
int x = g.size(); //I rows
int y = g[i].size(); //J columns
//wrap the edges with formula (x+n)%n where n = NumOfRows or NumOfCol
if(g[(((i+1)+x)%x)][(((j-1)+y)%y)]==true){//top left
count++;
}
else if(g[(((i+1)+x)%x)][j]==true){//top middle
count++;
}
else if(g[(((i+1)+x)%x)][(((j+1)+y)%y)]==true){//top right
count++;
}
else if(g[i][(((j-1)+y)%y)]==true){//left cell
count++;
}
else if(g[i][(((j+1)+y)%y)]==true){//right cell
count++;
}
else if(g[(((i-1)+x)%x)][(((j-1)+y)%y)]==true){ //bottom left
count++;
}
else if(g[(((i-1)+x)%x)][j]==true){//bottom middle
count++;
}
else if(g[(((i-1)+x)%x)][(((j+1)+y)%y)]==true){//bottom right
count++;
}
if (g[i][j]) {
if(count > 3 || count < 2) {//if alive cell has more than 3 or less than 2, die
newworld[i][j] = false;
}
else if (count == 2 || count == 3) { //remain the same
newworld[i][j] = g[i][j];
}
}
else if (g[i][j] == false) {//dead come alive
if(count == 3) {
newworld[i][j] = true;
}
}
}
}
}
void display(vector<vector<bool> >&a)
{
for(size_t row = 0; row <a.size(); row++) {
for(size_t column = 0; column <a[row].size(); column++){
if (a[row][column]) {
cout << 'O';
}
else {
cout << '.';
}
}
cout << '\n';
}
}
int main()
{
vector<vector<bool> > newworld;
generate(world,newworld);
display(newworld);
return 0;
}
The function generate has (at least) two problem.
count is initialized outside the nested loops, so it's never reset to zero (as it should, for every cell) and keeps growing.
All the conditions are mutually exclusive, so whenever one it's met, the others are skipped. There shouldn't be any else if, but only ifs.
Keeping the data structure you chose, you can rewrite that function as
using gof_t = std::vector<std::vector<bool>>;
void generate(gof_t& g, gof_t& newworld)
{
for(size_t i = 0, x = g.size(); i < x; i++)
{
for(size_t j = 0, y = g[i].size(); j < y; j++)
{
size_t i_prev = (i + x - 1) % x;
size_t i_next = (i + 1) % x;
size_t j_prev = (j + y - 1) % y;
size_t j_next = (j + 1) % y;
int count = g[i_prev][j_prev] + g[i_prev][j] + g[i_prev][j_next]
+ g[i ][j_prev] + g[i ][j_next]
+ g[i_next][j_prev] + g[i_next][j] + g[i_next][j_next];
newworld[i][j] = g[i][j] ? (count == 2 || count == 3) : (count == 3);
}
}
std::swap(g, newworld); // <-- Passing by non const reference, we can swap without copying
}
Live (pun intended), here.
I was wondering how I can loop through a two dimentional array if the size of the array is random, e.g 6x6 or 10x10 etc. The idea is to search for four of the same kind of characters, 'x' or 'o'. This is typically needed for a board game.
int main() {
int array_size = 5; // Size of array
int array_height = array_size;
bool turn = true; // true = player 1, false = player 2
bool there_is_a_winner = false;
char** p_connect_four = new char*[array_size];
for (int i = 0; i < array_size; i++) // Initialise the 2D array
{ // At the same time set a value "_" as blank field
p_connect_four[i] = new char[array_size];
for (int j = 0; j < array_size; j++) {
p_connect_four[i][j] = '_';
}
}
}
This is what I have so far, checking from [3][0] to [0][3]. But this requires me to add 2 more for loops to check [4][0] to [0][4] and [4][1] to [1][4] IF the size of the board was 5x5.
for (int i = 3, j = 0; i > 0 && j < array_size; i--, j++ ) {// CHECK DOWN up right from 3,0 -> 0,3
if (p_connect_four[i][j] == p_connect_four[i - 1][j + 1] && p_connect_four[i][j] != '_' ) {
check_diagonalRight++;
if (check_diagonalRight == 3) {
there_is_a_winner = true;
break;
}
}
else {
check_diagonalRight = 0;
}
}
if (there_is_a_winner) { // Break while loop of game.
break;
}
Obviously I want to check the whole board diagonally to the right regardless of the size of the board. Is there any other way than having 3 separate for loops for checking
[3][0] -> [0][3] , [4][0] -> [0][4] and [4][1]-> [1][4] ?
for (i = array_size - 1, j = array_size - 2;
i < array_size && i >= 0, j < array_size && j >= 0; j--)
{ // starts from [4][3] and loops to the left if arraysize = 5x5
// but works on any size
int k = i, l = j;
for (k, l; k < array_size && k > 0, l < array_size && l > 0; k--, l++)
{ // checks diagonally to the right
if (check_diagonalRight == 3)
{
there_is_a_winner = true;
break;
}
if (p_connect_four[k][l] == p_connect_four[k - 1][l + 1] &&
p_connect_four[k][l] != '_')
{ //check up one square and right one square
check_diagonalRight++;
}
else
{
check_diagonalRight = 0;
// if its not equal, reset counter.
}
}
if (there_is_a_winner)
{
break; // break for loop
}
}
if (there_is_a_winner)
{
break; // break while loop of game
}
This checks up and right no matter the size, implement it for the other angles as well and it will work for any board size. You could potentially check right and left diagonal at once with nested loops.
This will work perfectly fine for your program! I hope so!
int arraySize = 8;
for(int i=0, j=0; i<arraySize && j<arraySize; i++, j++)
{
if((i == 0 && j == 0) || (i == arraySize - 1 && j == arraySize - 1))
{
continue;
}
else
{
int k = i;
int l = j;
//This Loop will check from central line (principal diagonal) to up right side (like slash sign / (representing direction))
for(k, l; k>0 && l < arraySize - 1; k--, l++)
{
//Here check your condition and increment to your variable. like:
if (p_connect_four[k][l] == p_connect_four[k - 1][l + 1] && p_connect_four[k][l] != '_' )
{
check_diagonalRight++;
}
}
//You can break the loop here if check_diagonalRight != k then break
k = i;
l = j;
//This Loop will check from central line (principal diagonal) to down left side (like slash sign / (representing direction))
for(k, l; k<arraySize - 1 && l > 0; k++, l--)
{
//Here check your condition and increment to your variable. like:
if (p_connect_four[k][l] == p_connect_four[k + 1][l - 1] && p_connect_four[k][l] != '_' )
{
check_diagonalRight++;
}
}
if(check_diagonalRight == i+j+1)
{
there_is_a_winner = true;
break;
}
}
}
I suggest to surround your board with extra special cases to avoid to check the bound.
To test each direction I suggest to use an array of offset to apply.
Following may help:
#include <vector>
using board_t = std::vector<std::vector<char>>;
constexpr const std::size_t MaxAlignment = 4;
enum Case {
Empty = '_',
X = 'X',
O = 'O',
Bound = '.'
};
enum class AlignmentResult { X, O, None };
// Create a new board, valid index would be [1; size] because of surrounding.
board_t new_board(std::size_t size)
{
// Create an empty board
board_t board(size + 2, std::vector<char>(size + 2, Case::Empty));
// Add special surround.
for (std::size_t i = 0; i != size + 2; ++i) {
board[0][i] = Case::Bound;
board[size + 1][i] = Case::Bound;
board[i][0] = Case::Bound;
board[i][size + 1] = Case::Bound;
}
return board_t;
}
// Test a winner from position in given direction.
AlignmentResult test(
const board_t& board,
std::size_t x, std::size_t y,
int offset_x, int offset_y)
{
if (board[x][y] == Case::Empty) {
return AlignmentResult::None;
}
for (std::size_t i = 1; i != MaxAlignment; ++i) {
// Following condition fails when going 'out of bound' thanks to Case::Bound,
// else you have also to check size...
if (board[x][y] != board[x + i * offset_x][y + i * offset_y]) {
return AlignmentResult::None;
}
}
if (board[x][y] == Case::X) {
return AlignmentResult::X;
} else {
return AlignmentResult::O;
}
}
// Test a winner on all the board
AlignmentResult test(const board_t& board)
{
// offset for direction. Use only 4 direction because of the symmetry.
const int offsets_x[] = {1, 1, 1, 0};
const int offsets_y[] = {-1, 0, 1, 1};
const std::size_t size = board.size() - 1;
for (std::size_t x = 1; x != size; ++x) {
for (std::size_t y = 1; y != size; ++y) {
for (std::size_t dir = 0; dir != 4; ++dir) { // for each directions
auto res = test(board, x, y, offsets_x[dir], offsets_y[y]);
if (res != AlignmentResult::None) {
return res;
}
}
}
}
return AlignmentResult::None;
}
I am trying to make this go through the array in a spiral order. When it finds 2, it should replace it with 0 and the next number in the spiral order should become 2. So, if my array is
000
200
000
is should become
000
020
000
The variable ok tells me if I found that number 2 and simply modifies the next number to 2. Note that it doesn't loop through it. When It reaches the center of the array, it stops and doesn't go backwards or starts over.
Any ideas why it doesn't work? It simply doesn't modify my array at all.
#include<iostream>
using namespace std;
#define ROWS 3
#define COLS 3
int main()
{
int arr[ROWS][COLS] = {{2,0,0},
{0,0,0},
{0,0,0}};
// Four direction counters of current movement
// Horizontal right, vertical bottom, horizontal left and vertical top respectively
int hr, vb, hl, vt, ok=0;
// levl indicates current depth of our imaginary rectangle into array. Starting value is zero
// since we are looping on the boundaries and ending value is the inner most rectangle
int levl;
for (levl=0; levl < COLS - levl; levl++)
{
for(hr=levl; hr < COLS-levl; hr++) // go right
{
if (ok==1)
{
arr[levl][hr] == 2;
ok = 2;
}
if ( (arr[levl][hr] == 2) && (ok == 0) )
{
arr[levl][hr] == 0;
ok = 1;
}
}
for(vb=levl+1; vb < COLS-levl; vb++) // go down
{
if (ok == 1)
{
arr[vb][hr-1] == 2;
ok = 2;
}
if ( (arr[vb][hr-1] == 2) && (ok == 0) )
{
arr[vb][hr-1] == 0;
ok = 1;
}
}
for(hl=vb-1; hl-1 >= levl; hl--) // go left
{
if ( ok == 1)
{
arr[vb-1][hl-1] == 2;
ok = 2;
}
if ( (arr[vb-1][hl-1] == 2) && (ok == 0) )
{
arr[vb-1][hl-1] == 0;
ok = 1;
}
}
for(vt=vb-1; vt-1 > levl; vt--) // go up
{
if (ok == 1)
{
arr[vt-1][hl] == 2;
ok = 2;
}
if ( (arr[vt-1][hl] == 2) && (ok==0) )
{
arr[vt-1][hl] == 0;
ok = 1;
}
}
}
cout << endl;
for(int t = 0;t < 3;t++)
{
for(int u = 0;u < 3;u++)
cout<<arr[t][u]<<" ";
cout<<endl;
}
int a;
cin>>a;
return 0;
}
The reason that your array is not being modified is because you are using "==" instead of "=". So
if ((arr[levl][hr] == 2)&&(ok==0))
{
arr[levl][hr] == 0;
ok=1;
}
should be
if ((arr[levl][hr] == 2)&&(ok==0))
{
arr[levl][hr] = 0;
ok=1;
}
== Is a comparison operator and = assigns the value. Check your code very carefully and make it more readable for you could be able to find easy mistakes like that :).
I need to place numbers within a grid such that it doesn't collide with each other. This number placement should be random and can be horizontal or vertical. The numbers basically indicate the locations of the ships. So the points for the ships should be together and need to be random and should not collide.
I have tried it:
int main()
{
srand(time(NULL));
int Grid[64];
int battleShips;
bool battleShipFilled;
for(int i = 0; i < 64; i++)
Grid[i]=0;
for(int i = 1; i <= 5; i++)
{
battleShips = 1;
while(battleShips != 5)
{
int horizontal = rand()%2;
if(horizontal == 0)
{
battleShipFilled = false;
while(!battleShipFilled)
{
int row = rand()%8;
int column = rand()%8;
while(Grid[(row)*8+(column)] == 1)
{
row = rand()%8;
column = rand()%8;
}
int j = 0;
if(i == 1) j= (i+1);
else j= i;
for(int k = -j/2; k <= j/2; k++)
{
int numberOfCorrectLocation = 0;
while(numberOfCorrectLocation != j)
{
if(row+k> 0 && row+k<8)
{
if(Grid[(row+k)*8+(column)] == 1) break;
numberOfCorrectLocation++;
}
}
if(numberOfCorrectLocation !=i) break;
}
for(int k = -j/2; k <= j/2; k++)
Grid[(row+k)*8+(column)] = 1;
battleShipFilled = true;
}
battleShips++;
}
else
{
battleShipFilled = false;
while(!battleShipFilled)
{
int row = rand()%8;
int column = rand()%8;
while(Grid[(row)*8+(column)] == 1)
{
row = rand()%8;
column = rand()%8;
}
int j = 0;
if(i == 1) j= (i+1);
else j= i;
for(int k = -j/2; k <= j/2; k++)
{
int numberOfCorrectLocation = 0;
while(numberOfCorrectLocation != i)
{
if(row+k> 0 && row+k<8)
{
if(Grid[(row)*8+(column+k)] == 1) break;
numberOfCorrectLocation++;
}
}
if(numberOfCorrectLocation !=i) break;
}
for(int k = -j/2; k <= j/2; k++)
Grid[(row)*8+(column+k)] = 1;
battleShipFilled = true;
}
battleShips++;
}
}
}
}
But the code i have written is not able to generate the numbers randomly in the 8x8 grid.
Need some guidance on how to solve this. If there is any better way of doing it, please tell me...
How it should look:
What My code is doing:
Basically, I am placing 5 ships, each of different size on a grid. For each, I check whether I want to place it horizontally or vertically randomly. After that, I check whether the surrounding is filled up or not. If not, I place them there. Or I repeat the process.
Important Point: I need to use just while, for loops..
You are much better of using recursion for that problem. This will give your algorithm unwind possibility. What I mean is that you can deploy each ship and place next part at random end of the ship, then check the new placed ship part has adjacent tiles empty and progress to the next one. if it happens that its touches another ship it will due to recursive nature it will remove the placed tile and try on the other end. If the position of the ship is not valid it should place the ship in different place and start over.
I have used this solution in a word search game, where the board had to be populated with words to look for. Worked perfect.
This is a code from my word search game:
bool generate ( std::string word, BuzzLevel &level, CCPoint position, std::vector<CCPoint> &placed, CCSize lSize )
{
std::string cPiece;
if ( word.size() == 0 ) return true;
if ( !level.inBounds ( position ) ) return false;
cPiece += level.getPiece(position)->getLetter();
int l = cPiece.size();
if ( (cPiece != " ") && (word[0] != cPiece[0]) ) return false;
if ( pointInVec (position, placed) ) return false;
if ( position.x >= lSize.width || position.y >= lSize.height || position.x < 0 || position.y < 0 ) return false;
placed.push_back(position);
bool used[6];
for ( int t = 0; t < 6; t++ ) used[t] = false;
int adj;
while ( (adj = HexCoord::getRandomAdjacentUnique(used)) != -1 )
{
CCPoint nextPosition = HexCoord::getAdjacentGridPositionInDirection((eDirection) adj, position);
if ( generate ( word.substr(1, word.size()), level, nextPosition, placed, lSize ) ) return true;
}
placed.pop_back();
return false;
}
CCPoint getRandPoint ( CCSize size )
{
return CCPoint ( rand() % (int)size.width, rand() % (int)size.height);
}
void generateWholeLevel ( BuzzLevel &level,
blockInfo* info,
const CCSize &levelSize,
vector<CCLabelBMFont*> wordList
)
{
for ( vector<CCLabelBMFont*>::iterator iter = wordList.begin();
iter != wordList.end(); iter++ )
{
std::string cWord = (*iter)->getString();
// CCLog("Curront word %s", cWord.c_str() );
vector<CCPoint> wordPositions;
int iterations = 0;
while ( true )
{
iterations++;
//CCLog("iteration %i", iterations );
CCPoint cPoint = getRandPoint(levelSize);
if ( generate (cWord, level, cPoint, wordPositions, levelSize ) )
{
//Place pieces here
for ( int t = 0; t < cWord.size(); t++ )
{
level.getPiece(wordPositions[t])->addLetter(cWord[t]);
}
break;
}
if ( iterations > 1500 )
{
level.clear();
generateWholeLevel(level, info, levelSize, wordList);
return;
}
}
}
}
I might add that shaped used in the game was a honeycomb. Letter could wind in any direction, so the code above is way more complex then what you are looking for I guess, but will provide a starting point.
I will provide something more suitable when I get back home as I don't have enough time now.
I can see a potential infinite loop in your code
int j = 0;
if(i == 1) j= (i+1);
else j= i;
for(int k = -j/2; k <= j/2; k++)
{
int numberOfCorrectLocation = 0;
while(numberOfCorrectLocation != i)
{
if(row+k> 0 && row+k<8)
{
if(Grid[(row)*8+(column+k)] == 1) break;
numberOfCorrectLocation++;
}
}
if(numberOfCorrectLocation !=i) break;
}
Here, nothing prevents row from being 0, as it was assignd rand%8 earlier, and k can be assigned a negative value (since j can be positive). Once that happens nothing will end the while loop.
Also, I would recommend re-approaching this problem in a more object oriented way (or at the very least breaking up the code in main() into multiple, shorter functions). Personally I found the code a little difficult to follow.
A very quick and probably buggy example of how you could really clean your solution up and make it more flexible by using some OOP:
enum Orientation {
Horizontal,
Vertical
};
struct Ship {
Ship(unsigned l = 1, bool o = Horizontal) : length(l), orientation(o) {}
unsigned char length;
bool orientation;
};
class Grid {
public:
Grid(const unsigned w = 8, const unsigned h = 8) : _w(w), _h(h) {
grid.resize(w * h);
foreach (Ship * sp, grid) {
sp = nullptr;
}
}
bool addShip(Ship * s, unsigned x, unsigned y) {
if ((x <= _w) && (y <= _h)) { // if in valid range
if (s->orientation == Horizontal) {
if ((x + s->length) <= _w) { // if not too big
int p = 0; //check if occupied
for (int c1 = 0; c1 < s->length; ++c1) if (grid[y * _w + x + p++]) return false;
p = 0; // occupy if not
for (int c1 = 0; c1 < s->length; ++c1) grid[y * _w + x + p++] = s;
return true;
} else return false;
} else {
if ((y + s->length) <= _h) {
int p = 0; // check
for (int c1 = 0; c1 < s->length; ++c1) {
if (grid[y * _w + x + p]) return false;
p += _w;
}
p = 0; // occupy
for (int c1 = 0; c1 < s->length; ++c1) {
grid[y * _w + x + p] = s;
p += _w;
}
return true;
} else return false;
}
} else return false;
}
void drawGrid() {
for (int y = 0; y < _h; ++y) {
for (int x = 0; x < _w; ++x) {
if (grid.at(y * w + x)) cout << "|S";
else cout << "|_";
}
cout << "|" << endl;
}
cout << endl;
}
void hitXY(unsigned x, unsigned y) {
if ((x <= _w) && (y <= _h)) {
if (grid[y * _w + x]) cout << "You sunk my battleship" << endl;
else cout << "Nothing..." << endl;
}
}
private:
QVector<Ship *> grid;
unsigned _w, _h;
};
The basic idea is create a grid of arbitrary size and give it the ability to "load" ships of arbitrary length at arbitrary coordinates. You need to check if the size is not too much and if the tiles aren't already occupied, that's pretty much it, the other thing is orientation - if horizontal then increment is +1, if vertical increment is + width.
This gives flexibility to use the methods to quickly populate the grid with random data:
int main() {
Grid g(20, 20);
g.drawGrid();
unsigned shipCount = 20;
while (shipCount) {
Ship * s = new Ship(qrand() % 8 + 2, qrand() %2);
if (g.addShip(s, qrand() % 20, qrand() % 20)) --shipCount;
else delete s;
}
cout << endl;
g.drawGrid();
for (int i = 0; i < 20; ++i) g.hitXY(qrand() % 20, qrand() % 20);
}
Naturally, you can extend it further, make hit ships sink and disappear from the grid, make it possible to move ships around and flip their orientation. You can even use diagonal orientation. A lot of flexibility and potential to harness by refining an OOP based solution.
Obviously, you will put some limits in production code, as currently you can create grids of 0x0 and ships of length 0. It's just a quick example anyway. I am using Qt and therefore Qt containers, but its just the same with std containers.
I tried to rewrite your program in Java, it works as required. Feel free to ask anything that is not clearly coded. I didn't rechecked it so it may have errors of its own. It can be further optimized and cleaned but as it is past midnight around here, I would rather not do that at the moment :)
public static void main(String[] args) {
Random generator = new Random();
int Grid[][] = new int[8][8];
for (int battleShips = 0; battleShips < 5; battleShips++) {
boolean isHorizontal = generator.nextInt(2) == 0 ? true : false;
boolean battleShipFilled = false;
while (!battleShipFilled) {
// Select a random row and column for trial
int row = generator.nextInt(8);
int column = generator.nextInt(8);
while (Grid[row][column] == 1) {
row = generator.nextInt(8);
column = generator.nextInt(8);
}
int lengthOfBattleship = 0;
if (battleShips == 0) // Smallest ship should be of length 2
lengthOfBattleship = (battleShips + 2);
else // Other 4 ships has the length of 2, 3, 4 & 5
lengthOfBattleship = battleShips + 1;
int numberOfCorrectLocation = 0;
for (int k = 0; k < lengthOfBattleship; k++) {
if (isHorizontal && row + k > 0 && row + k < 8) {
if (Grid[row + k][column] == 1)
break;
} else if (!isHorizontal && column + k > 0 && column + k < 8) {
if (Grid[row][column + k] == 1)
break;
} else {
break;
}
numberOfCorrectLocation++;
}
if (numberOfCorrectLocation == lengthOfBattleship) {
for (int k = 0; k < lengthOfBattleship; k++) {
if (isHorizontal)
Grid[row + k][column] = 1;
else
Grid[row][column + k] = 1;
}
battleShipFilled = true;
}
}
}
}
Some important points.
As #Kindread said in an another answer, the code has an infinite loop condition which must be eliminated.
This algorithm will use too much resources to find a solution, it should be optimized.
Code duplications should be avoided as it will result in more maintenance cost (which might not be a problem for this specific case), and possible bugs.
Hope this answer helps...