将对象推送到矢量中

Question

I am trying to write a piece of code that takes an object and pushes it onto the back of a vector, but the objects are not being pushed correctly.

I am writing an OpenGL application and I want to draw many lines in it. In order to store those lines, I first create each line in a C2DPointSet and when I stop drawing, I want to push the current line in my vector of lines. By debugging the code, I saw that the length of the vector after pushing the line is 0 and the same line in the vector has 0 points (which should not be the case). Here is the code:

vector <C2DPointSet> lines; //global variables
C2DPointSet line;

//function that runs if a button is pressed and i click in my glwindow
void lineButtonFunction(int x,int y){
    C2DPoint currentPoint;  
    currentPoint=workspacePoint(x,y);//returns point;s cordinates acording to cursorx,y-it works
    line.AddCopy(currentPoint);//adds a copy of the given point to obj line
}


//code that runs when i am done drawing 
if(buttons[i].getButtonText()=='L'){ 
    lines.push_back(line);
    line.DeleteAll();//empties the obj
}

I don't know what the problem is. With different objects the code would run. I am not sure, but i think that the problem stems from pushing C2DPointSet because it stores as many points as I like. Also, I observed that regardless of how many points I stored in the line I got its size as 12.

C2DPoints and C2DPointSet are from geolib; information can be found here .

Answer 1

It appears that C2DPointSet has a constructor and a destructor, but no copy constructor and copy assignment operator, ie C2DPointSet does not follow the rule of three . This is problematic if C2DPointSet has pointer members. Does it? Then it is inherently broken. It just won't work in vectors.

Answer 2

Maybe it depends on the contents of C2DPointSet class. Possible that you don't have copy constructor there. My suggestion is to have a vector of references instead of vector of actual objects. That way you will also minimize the overhead. So you should have vector<&C2DPointSet> lines, instead of what you have. Try it. It might work.