Databases
StackOverflow2013
Postsdbo
POAccessing a property of a pointer in a struct
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POAccessing a property of a pointer in a struct
    primarykey
    data
    text
    <p>First of I have 2 Classes in 2 files (both .h and .cpp files), <em>Create.h</em> and <em>AI.h</em>.</p> <p>Create.h has this struct in it:</p> <pre><code>public: struct Cell { int row; int column; vector&lt;Cell*&gt; neighbors; State state; }; </code></pre> <p>Here is the enum class State (stored in the Create.h file):</p> <pre><code>enum class State : char { visited, empty }; </code></pre> <p>In AI.h I have a stack and a Create object like this:</p> <pre><code>private: deque&lt;Create::Cell*&gt; path; Create obj; </code></pre> <p>In AI.cpp there is an instance called <em>obj</em> which contains a 2D array of Cell where every Cell has row, column, state and neighbors set appropriately.</p> <p>Constructor:</p> <pre><code>AI::AI(Create createObj) : obj(createObj) { start = &amp;obj.array[1][1]; } </code></pre> <p>I also have a function like this which starts with <code>start</code> as an argument:</p> <pre><code>void AI::Function(Create::Cell* cell) { path.push_back(cell); cell-&gt;state = State::visited; while (expression) { cell = path.back(); cell-&gt;state = State::visited; for (int i = 0; i &lt; cell-&gt;neighbors.size(); i++) { if (cell-&gt;neighbors[i]-&gt;state == State::empty) { path.push_back(cell-&gt;neighbors[i]); } } } } </code></pre> <p>So basically the cell in the path stack starts by pointing to the obj.array[1][1] and sets it correctly (I have confirmed that it actually points where I want it to) but when I retrieve a cell from the stack it doesn't point to the obj.array.</p> <p>What I am trying to do is to set the state of the neighbors of each cell but I manage to set the state on the <em>path</em> stack, on the cell itself but NOT on the array inside the obj instance.</p> <p>What I definitely can do and it works is set the obj.array[i][j] under the cell like this:</p> <pre><code>cell = path.back(); cell-&gt;state = State::visited; obj.array[cell-&gt;row][cell-&gt;column].state = State::visited; </code></pre> <p>What I wanted to know is if there is a way (through pointers I presume) to make the obj.array Cell element know that it's being set by the <em>cell->state = State::visited;</em></p>
    singulars
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PTQuestion
    1. USMadison Scodelario
    1. USMadison Scodelario
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. COIf I understand this properly then your problem will be solved if the path cell pointers point to the obj array. So I guess the question is how you are adding the cell pointers to the path, and is there any reason why they shouldn't point to the obj array?
      singulars
      1. POAccessing a property of a pointer in a struct
      1. USjohn
    2. COThe cell pointers are added through this `path.push_back(cell);` (I am not sure if that is your question though). I don't think there would be a problem to make them point to the obj.array but how would I do that? Making the path a pointer-to-pointer Cell deque? Because I am pretty sure I tried that earlier and I had a lot of problems with it.
      singulars
      1. POAccessing a property of a pointer in a struct
      1. USMadison Scodelario
    3. COSo `path` is.... what ? a `std::deque< Create::Cell* >` ? And is it in your wheelhouse to use `std::shared_ptr<Create::Cell>` for all of this and stop the insanity of the raw-pointer extravaganza?
      singulars
      1. POAccessing a property of a pointer in a struct
      1. USWhozCraig
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload