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Make Games With Us: Game of Life: Objective-C Property Error

I have been attempting to follow on how to make John Conway's 'Game of Life' through 'Make Games With Us'. I was able to follow for most of the tutorial until I reached in the step method of MainScene.m (here is the link to the site):

- (void)step
{
    [_grid evolveStep]
    _generationLabel.string = [NSString stringWithFormat:@"%d", _grid.generation];
    _populationLabel.string = [NSString stringWithFormat:@"%d", _grid.totalAlive];
}

The errors are of the same type; they're showing up at _grid.generation and _grid.totalAlive. The error is the following:

Property 'generation' not found on object of type 'Grid *'
Property 'totalAlive' not found on object of type 'Grid *'

I have looked at this link on how to fix the very same issue, yet I saved and published everything correctly in SpriteBuilder; the user apparently solved it, but I cannot find out how.

Update: Missing Property Declaration (Grid.m):

#import "Grid.h"
#import "Creature.h"

// variables that cannot be changed
static const int GRID_ROWS = 8;
static const int GRID_COLUMNS = 10;

@implementation Grid {
    NSMutableArray *_gridArray;
    float _cellWidth;
    float _cellHeight;
    int _generation; // This one
    int _totalAlive; // This one
}

/*Rest of the methods go here*/

@end

Thank you in advance!

Solution

  • This unfortunately was a mistake in our tutorial.

    Indeed you need to add two properties to Grid.h:

    @property (nonatomic, assign) int totalAlive;
@property (nonatomic, assign) int generation;

    Instead of adding instance variables to Grid.m.

    The tutorial has now been updated: https://www.makegameswith.us/tutorials/game-of-life-spritebuilder/game-of-life-code/

    You can also find the entire code for the solution on GitHub: https://github.com/MakeGamesWithUs/GameOfLife.spritebuilder

    Sorry for the inconvenience!