C ++如何直接调用在类中定义的方法，其中仅对该类的引用由另一个函数返回

Question

In my program, I have a grid class (eg myGrid ) and I could obtain a reference to a cell (a class) by overloading the operator() . My problem is each time I call this myGrid(x, y) which returns a reference to a cell, I need to claim a cell reference.

 cell& myCell = myGrid(x,y);
 myCell.status = currentStatus; 

I got an error by doing this:

(myGrid(x,y)).status = currentStatus;

I need to use the function defined in cell very frequently. Thus, each time I need to claim a cell reference which makes my code look urgly. Is there any elegant way to solve the problem? Thanks very much. Cheers!

Sorry. There is a typo. Let's assume status is a public varible in cell and assume currentStatus is a variable of the same type as status.

Grid is a predefined class and I don't have the right to modify it. It returns a reference to cell. Eg cell& operator()(int x, int y)

Sorry for the chaos. myGrid(x,y).status works. I made a mistake somewhere before. When I complied it, the error occurred in this line. Thanks very much!

Answer 1

the object of function-myGrid(x,y) return ,maybe out of scope. I mean, the object you return may be a local variable.

Answer 2

How your operator() defined (signature)? What is the signature of status ? They should be cell& operator() (int x, int y); and int& status(); . Provide minimal example that doesn't work.

And the best way and elegant is to use explicit methods:

myGrid.GetCell(x, y).SetStatus(s);

This is much more readable and supportable. Also, using getter/setter instead of returning a reference may allow you control point where value changed - you may log there or set a breakpoint. Returning reference is poor practice - you may never be sure will it be changed or only read after.