CODEWITHSUNDEEP
c++pointersmultidimensional-array
Pinet
Pinet

Reputation: 29

Trying to use multidimensional array pointers

I was searching for a solution, but I couldn't use any without an error. Im trying to draw a map in console, using multidismentional array. I want to have more maps, but I can`t do it without spamming useless code. This is the map:

char map2[11][15] = {
"###^######^###",
"#L           #",
"^S           #",
"#S           #",
"#    K       #",
"###########  #",
"#G           #",
"#       #### #",
"#       #M   #",
"# @     #    #",
"## ########^##"};

and this is moving script:

void Game::showing_different_maps()
{
    differentmap= true;
    while (differentmap)
    {
        system("cls");
        for(int i = 0; i < 81; i++)  // i < map2[y][]
        {
            cout << somemap[i] << endl; // drawing a map !THIS CAUSES CRASH!
        }
    system("pause>nul"); // this line prevent lagging somehow

        if(GetAsyncKeyState(VK_UP))  // arrows to move on axis (y, x)
        {
            mapka.move(-1, 0);                    
        }
        if(GetAsyncKeyState(VK_DOWN))
        {
            mapka.move(1, 0);
        }
        if(GetAsyncKeyState(VK_RIGHT))
        {
            mapka.move(0, 1);
        }
        if(GetAsyncKeyState(VK_LEFT))
        {
            mapka.move(0, -1);
        }

    }

}

and here is what I could find in the internet.

  Wut wut(3, 13);
  Maps *wsk;
  pointer = &wut;

  char (*somemap)[81] = new char[81][81];
  somemap= &map2[81];

  pointer = &wut;
  pointer -> get_in_area();

thing I want to do is to: in some part of the code, I want the pointer to be map2. I managed to make pointer "pointer" to show void get_in_area() in class Maps, but Console crashes, when I want to draw the map with somemap pointer in second code sample. It works, when instead of somemap[i] I put map2[i]. I`m sorry if I missed anything, I'm beginner and English is not my first language. I made this script with this tutorial: https://www.youtube.com/watch?v=7gpH7bOS350

Upvotes: 1

Views: 89

Answers (2)

Serge Ballesta
Serge Ballesta

Reputation: 148880

You should learn how to pass parameters instead of using global (map2) or static (81) variables. If you declare:

void Game::showing_different_maps(int n, int m, char map[n][m])
{
 String   differentmap= true;
    while (differentmap)
    {
        system("cls");
        for(int i = 0; i < n; i++)  // i < map2[y][]
        {
            cout << somemap[i] << endl; // drawing a map !THIS CAUSES CRASH!
        }

you should no longer crash...

But anyway, for this usage, I would use a pointer to pointer instead of a 2d array:

char *map2[]= {
  "###^######^###",
  "#L           #",
  "^S           #",
  "#S           #",
  "#    K       #",
  "###########  #",
  "#G           #",
  "#       #### #",
  "#       #M   #",
  "# @     #    #",
  "## ########^##"};

And then

void Game::showing_different_maps(int n, char **map)

Upvotes: 0

user6499716
user6499716

Reputation:

This is how you would create a 2-dimensional array: 

typedef int T;
void f()
{

    T ** map = new T*[10];

    for (int i = 0; i < 10; i++)
    {
        map[i] = new T[10];
    }

    for (int i = 0; i < 10; i++)
    {
        for (int j = 0; j < 10; j++)
        {
            map[i][j] = i*j;
        }
    }

    for (int i = 0; i < 10; i++)
    {
        for (int j = 0; j < 10; j++)
        {
            std::cout << map[i][j] << "\t";
        }
        std::cout << std::endl;
    }
}

This will output a generic multiplication table.

If you want more dimensions you would simply add one more step in creation:

T*** map = new T**[10];

for (int i = 0; i < 10; i++)
{
    map[i] = new T*[10];
}
...

Upvotes: 1

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