Question

I have a data like BigArr, arr, … declared in header:

class TableView:public QWidget 
{
  Q_OBJECT

  public:TableView (QWidget * parent = 0);

  std::vector < TXdata >  BigArr;

  std::vector < float >  arr;
  std::vector < float >  arr2;
  std::vector < int >  arrlocKtab;
  std::vector < int >  arrlocKrow;

In source file I have some functions I copy/pasted from somewhere else, like:

static void
 multiply (float q[4], float value)
{
  q[0] *= value;
  q[1] *= value;
  q[2] *= value;
  q[3] *= value;
}

and some other functions I made, like:

 void
 TableView::ShowContextMenu (const QPoint & pos)    // this is a slot
 {

How do I get declarations from header file to work inside copy/pasted functions. Like:

  static void
     multiply (float q[4], float value)
    {

  arr[0]= something...

I got some bad results from renaming c/p functions to void TableView::function and adding them to function list in the header file. Probably something to do with the static void &static inline void… Ty

Answer 1

You have to define the multiply function as part of the TableView class as follows:

class TableView:public QWidget 
{
    ...
    void multiply(float q[4], float value);
    ...
};

Then define it in the source file like this:

void TableView::multiply(float q[4], float value)
{
    ...
    arr[0] = something;
    ...
}

Or you pass an instance of TableView into multiply() if you cant/dont want to make it a member of TableView. If you decide to pass in an instance of TableView to the function, then you’ll have to consider how to access the class members, either by making a getter function or making them public. The getter acccessor function is a cleaner solution.

Either way will work, but if you decide to make everything member functions, consider the design and make sure the class doesnt become bloated, called low cohesion: en.wikipedia.org/wiki/Single_responsibility_principle