help with code, please

[ABU-YAGHI]

can any one help me with this code?

[Oleksandr Medviediev]

ABU-YAGHI:
can any one help me with this code?

Traders and coders are working for free:
 -- if it is interesting for them personally, or
 -- if it is interesting for many members on this forum.

Freelance section of the forum should be used in most of the cases.

[Kazutaka Okuno]

The compilation errors were primarily caused by:

• Incompatible syntax: MQL5 has strict limitations on operator overloading for structures.

• Incorrect function signatures: The method required more arguments than provided. Attach

• Library differences: The class uses rather than to release resources. CCanvas Destroy() Detach()

	Original Code	Corrected Code	Note
	bool operator==(...)	Removed (Moved to a method within ViewportState )	MQL5 doesn't support global equality operators for structs in this context.
	m_canvas.Attach(m_obj_name)	m_canvas.Attach(0, m_obj_name, COLOR_FORMAT_ARGB_NORMALIZE)	Added the missing Chart ID and Color Format parameters.
	m_canvas.Detach()	m_canvas.Destroy()	Replaced with the valid method name for the CCanvas library.
	if(cur != g_last_viewport_state)	if(cur.IsChanged(g_last_viewport_state))	Updated the logic to call the newly created comparison method.

Technical Explanation

1. Operator Overloading: Instead of using global operators, we implemented a member function (e.g., ) within the structure to compare states. IsChanged ViewportState

2. CCanvas Method Signatures: The method in MQL5's requires a minimum of three arguments: , , and . Attach Canvas.mqh chart_id obj_name color_format

3. Resource Management: In the standard class, is the proper method to clean up the canvas object and detach it from the chart. CCanvas Destroy()

[Vladislav Boyko]

Kazutaka Okuno #:
Incompatible syntax: MQL5 has strict limitations on operator overloading for structures.

What are you talking about? Operation overloading works great for structures.

struct S
  {
private:
   int x;
public:
   bool operator==(const S& other) { return x == other.x; }
   S(int a_x) : x(a_x) {}
  };

#define _print(x) Print(#x" --> ", (x))
void OnStart()
  {
   S one(1);
   S two(2);
   _print(one == one);
   _print(one == two);
  }

Output:

one == one --> true

one == two --> false