Any questions from newcomers on MQL4 and MQL5, help and discussion on algorithms and codes - page 510

[Juer]

A question about the algorithm. Who here understands theoretical and mathematical statistics? Look, there is a price series, levels. I need to select "strong" levels from them. Strong means the value where the frequency of distribution of these levels is the highest.

For example, the series 1,8,10,11,13,35,40,60,65. Say there is a delta, say 2, which denotes the maximum difference between the values. So there is a strong level around 8,10,11,13 which equals (8+10+11+13)/4. Maybe there's just a ready-made statistical function for this, so I don't have to reinvent the wheel? Can you give me a hint, please?

[Juer]

Please tell me, there are standard CArray classes for working with arrays. As I understand it, are they for working exclusively with one-dimensional arrays? Or with multidimensional (two-dimensional) arrays too? If not, is there a class for working with multidimensional arrays.

[Juer]

Juer:
Please tell me, there are standard CArray classes for working with arrays. As I understand it, are they for working exclusively with one-dimensional arrays? Or with multidimensional (two-dimensional) as well? If not, is there a class for working with multidimensional arrays?

https://www.mql5.com/ru/articles/567

Found here.

[Juer]

How do I return an array of structures in a function?

custom_struct values[];
...
custom_struct Func(void)
  {
   return GetPointer(values);
  }

class type expected, object required errors.

What is the correct way?

[Artyom Trishkin]

Juer:

How do I return an array of structures in a function?

class type expected, object required errors.

What is the correct way?

The pointer can be to an object of a class, but not to a structure

[Ihor Herasko]

Juer:

How do I return an array of structures in a function?

class type expected, object required errors.

What is the correct way to do this?

Pass by reference:

struct A
{
...
};

A structA[];

void GetStructA(A &structA[])
{
....
   structA = _structA;
}

This is if the structure only contains simple data types (no strings or arrays). If the structure contains strings and/or arrays, then add an assignment operator overload to the structure.

[Juer]

Ihor Herasko:

Transfer by reference:

This is if the structure only contains simple data types (no strings and arrays). If the structure contains strings and/or arrays, then add an assignment operator overload to the structure.

So error invalid array access.

There are no arrays or strings in the structure. Only bool, integer, double and enums.

[Artyom Trishkin]

Juer:

So the error is invalid array access.

Do you just have a structure, not an array of structures?

You don't show the code normally. Do we have to guess?

[Juer]

Artyom Trishkin:

You just have a structure, not an array of structures?

You don't show the code properly. Do we have to guess?

An array of structures, I wrote it...

[Juer]

class CCandleRule : public CObject
  {
protected:
   input_rule        rules[];
public:
   void              GetRulesArray(input_rule &rules_array[]);
  }

void CCandleRule::GetRulesArray(input_rule &rules_array[])
  {
   rules_array=rules;
  }

The input_rule structure is large, but only has int, double, bool and enum fields. It does not contain strings or arrays.