Using Structs in C - c

Question

Hi im building a simple game in c (im new to the language). Im using the following structs:
typedef struct
{
int adjacent_mines;
bool revealed;
bool is_mine;
} Tile;
struct GameState
{
Tile tiles[NUM_TILES_X][NUM_TILES_Y];
};
typedef struct GameState GameState;
Im wondering how to properly call and set the structs? I have the following code where i would like to set state of each Tile.
void intialize_mines(){
for (int i =0; i < NUM_TILES_X; i++){
for (int j =0; j < NUM_TILES_Y; j++){
tiles[i,j].revealed = false;
}
}
}
But according to my console output i have done this incorrectly. How would i go about setting this correctly?

Answer 1

struct GameState just declares a type (just as int is just a type). You have to create a real struct in memory with GameState foo; similar to a normal variable (int foo;). And you can not access the contents of a struct without referencing the struct like foo.tiles. tiles on it's own is not known in this scope.
Afterwards you can access the struct with foo.tiles[i][j].revealed.
But to have access to this struct in your function you either have to pass it to the function as a pointer or declare the struct in filescope ( also called global). I would prefer the first version it is clearer an more function like.
Your function would look like this:
void intialize_mines( GameState *foo){
for (int i =0; i < NUM_TILES_X; i++){
for (int j =0; j < NUM_TILES_Y; j++){
foo->tiles[i][j].revealed = false; // -> is a special operator for pointers to structs. It's the same as (*foo).
}
}
}
the corresponding function call would be:
GameSate bar;
intialize_mines( GameState &bar);
You should also check how to use multidimensional arrays. You declared it correctly with two seperate [] but in your function you use [x,y] which is not correct in C. It would be the same as in the declaration tiles[i][j]

Answer 2

For a multi-dimensional array like tiles, you have to specify array subscript of each dimension within [] like this:
tiles[i][j].revealed = false;
This means that revealed belonging to jth column of ith row of tiles is set to false.
And you will have to define a structure variable of the type GameState before performing any operations on it.
GameState initGS;
void intialize_mines(){
for (int i =0; i < NUM_TILES_X; i++){
for (int j =0; j < NUM_TILES_Y; j++){
initGS.tiles[i][j].revealed = false;
}
}
}

Answer 3

You just missed to instantiate a GameState structure.
GameState gs;
void initialize_mines() {
for (int i =0; i < NUM_TILES_X; i++) {
for (int j =0; j < NUM_TILES_Y; j++) {
gs.tiles[i][j].revealed = false;
}
}
}