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John Conway's Game of Life Assignment

moot (9)
I need to recreate the Game of Life by John Conway. My professor gave us the skeleton code, so all we had to do was fill out the functions. I have been having trouble finding out what is wrong with my code. It compiles correctly, it just doesn't output the next generation. It outputs the same array every single time. Any ideas?

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#include<iostream>
#include<cstdlib>

using namespace std;

const int BOARDCOLS=80;
const int BOARDROWS=22;
const int LIVE = 1;
const int DEAD = 0;


void generate(int[][BOARDCOLS],int[][BOARDCOLS]);
int checkneighbors(int[][BOARDCOLS]);
void copy(int[][BOARDCOLS],int[][BOARDCOLS]);
void display(int[][BOARDCOLS]);

int main()
{
    char next='n';
    int nextboard[BOARDROWS][BOARDCOLS];
    int currentboard[BOARDROWS][BOARDCOLS] =
    {
     {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},
     {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
     {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},
     {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
     {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},
     {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
     {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
     {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},
     {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
     {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
     {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
     {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
     {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},
     {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
     {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},
     {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
     {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
     {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},
     {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
     {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},
     {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
     {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
    };

    copy(currentboard, nextboard);

    while(next=='n')
    {
        display(currentboard);
        generate(currentboard,nextboard);
        copy(currentboard,nextboard);
        cin >> next;
    }
    return 0;
}


// Generate the next world
void generate(int currentboard[][BOARDCOLS], int nextboard[][BOARDCOLS])
{
    // http://pmav.eu/stuff/javascript-game-of-life-v3.1.1/
    /**
    Any live cell with fewer than two live neighbors dies, as if caused by under-population.
    Any live cell with two or three live neighbors lives on to the next generation.
    Any live cell with more than three live neighbors dies, as if by over-population.
    Any dead cell with exactly three live neighbors becomes a live cell, as if by reproduction.
    */
    // iterate over currentboard
    //   call checkneighbors with current cell and current row and column
    //   apply rules and use the result to add either a new cell or leave the current cell alone in the next board

    
    int neighbors = checkneighbors(currentboard);
    for (int r = 0; r < BOARDROWS; r++)
    {
        for (int c = 0; c < BOARDCOLS; c++)
        {
            if (currentboard[r][c] == LIVE && neighbors < 2)
            {
                nextboard[r][c] = DEAD;
            }
            else if (currentboard[r][c] == LIVE && (neighbors == 2 || neighbors == 3))
            {
                nextboard[r][c] = LIVE;
            }
            else if (currentboard[r][c] == LIVE && neighbors > 3)
            {
                nextboard[r][c] = DEAD;
            }
            else if (currentboard[r][c] == DEAD && neighbors == 3)
            {
                nextboard[r][c] = LIVE;
            }
        }
    }

}

// check the neighbors
//will check each 8 neighbors and add to the counter if it spots a 1
//will return the final counter
int checkneighbors(int board[][BOARDCOLS])
{
    int neighbor_count = 0;
    for (int r = 0; r < BOARDROWS; r++)
    {
        for (int c=0; c < BOARDCOLS; c++)
        {
            if (board[r][c-1] == LIVE)
            {
                neighbor_count++;
            }
            else if (board[r-1][c-1] == LIVE)
            {
                neighbor_count++;
            }
            else if (board[r-1][c] == LIVE)
            {
                neighbor_count++;
            }
            else if (board[r-1][c+1] == LIVE)
            {
                neighbor_count++;
            }
            else if (board[r][c+1] == LIVE)
            {
                neighbor_count++;
            }
            else if (board[r+1][c+1] == LIVE)
            {
                neighbor_count++;
            }
            else if (board[r+1][c] == LIVE)
            {
                neighbor_count++;
            }
            else if (board[r+1][c-1] == LIVE)
            {
                neighbor_count++;
            }
        }
    }
    return neighbor_count;
}

// copy one board to another
void copy(int source[][BOARDCOLS], int dest[][BOARDCOLS])
{
    for (int r = 0; r < BOARDROWS; r++)
    {
        for (int c = 0; c < BOARDCOLS; c++)
        {
            dest[r][c] = source[r][c];
        }
    }
}

// display the board
void display(int board[][BOARDCOLS])
{
    for (int r = 0; r < BOARDROWS; r++)
    {
        for (int c = 0; c < BOARDCOLS; c++)
        {
            cout << board[r][c];
        }
    } cout << endl;
}
Last edited on
helios (17575)
The skeleton code is incorrect. Line 53 should be copy(nextboard, currentboard);.
moot (9)
@helios: That ended up changing my output, but now it just prints all 0's instead of the next generation. Thanks for that though! Any ideas on the new problem? Also, for the skeleton code he gave us, the start of the definition for the 
checkneighbors
function was 
int checkneighbors(int board[][BOARDCOLS],int row,int col,int ROWS,int COLS)
, but I couldn't think of why it needed the last four parameters.
Last edited on
helios (17575)
You have to check the neighbors around a specific cell. Your function is checking the entire board.
moot (9)
@helios: So, would I have to add line 75 
int neighbors = checkneighbors(currentboard);
in the nested for loop after line 79 and add two more parameters? so then it will be 
int neighbors = checkneighbors(currentboard, r, c);
?
Am I on the right track? I tried that, but am still getting all the zeros. Again, thank you very much for the replies.
helios (17575)
Yes, and you also need to fix checkneighbors() itself.
moot (9)
@helios, wow, I can't believe I missed that! I ended up changing them to all if statements and now it outputs correctly. Thanks again!
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