Question

Static method are use in constructor or not

Answer 1

Static methods cannot be used by constructors in the same class. This is because static methods belong to the class itself, not to instances of the class. Constructors, on the other hand, are used to initialize instances of the class. When a constructor is called, there is no instance of the class yet, so it cannot access static methods. However, a constructor can call a static method of another class. Additionally, a static method can be used to initialize a static variable in the same class, which can then be used in the constructor.

Comments

Absolutely not.

Static methods belong to the class, not to the instance, thus you can call static methods just fine without the pointer/reference to the instance. See my example above/below.

Answer 2

Yes, you can use static methods in constructors as these static methods do not need a pointer to the object (in construction).

Similarly, static methods can be used to create an instance of the same class (think of a factory method).

You did not specify the language, so I went with C++, but similar logic works in C# and should work in other languages as well. See the example below:

Foo.h

#pragma once

class Foo
{
private:
    int value;

    static void DoSomething();

public:
    static Foo * CreateFoo();
    
    Foo();

    int GetValue();
};

Foo.cpp

#include "Foo.h"

#include <iostream>

void Foo::Initialize()
{
    std::cout << "static void Foo::DoSomething()" << std::endl;
}

Foo * Foo::CreateFoo()
{
    std::cout << "static Foo * Foo::CreateFoo()" << std::endl;
    return new Foo(); // Calling a constructor from a static method
}
    
Foo::Foo()
{
    std::cout << "Foo::Foo()" << std::endl;
    DoSomething(); // Calling a static method from the constructor
    value = 42;
}

int Foo::GetValue()
{
    return value;
}

main.cpp

#include "Foo.h"

#include <iostream>

int main()
{
    Foo * f1 = new Foo();
    std::cout << "Foo's value is: " << f1->GetValue() << std::endl;
    delete f1;

    Foo * f2 = Foo::CreateFoo();
    std::cout << "Foo's value is: " << f2->GetValue() << std::endl;
    delete f2;

    return 0;
}

Answer 3

static method are not used in constructor