What is the order in which the destructors and the constructors are called in C++

When you create an instance of a derived class, the code in the underlying constructor is called before the code in the derived constructor, but the derived class is still technically "created" before "creation" Please be careful. Foundation

When invoking a derived class's destructor, it is correct to call the destructor's code before the underlying destructor's code, but be aware that the base class is destroyed before derivation.

Looking at the memory layout of these instances, you can see that the derived instance constitutes the base instance. For example,

Therefore, you need to assign a derived class before the structure basis. Derived classes need to deallocate after discarding the basis

So, if you created Derived d, then if you get out of range, you will get @ Brian's answer. However, the behavior of objects in memory is not actually in the same order. It is as follows.

Every time you create an object of class A, its constructor needs to call class B and class C constructors. If not, the compiler calls the default constructors of B and C. But what if you want to call a constructor other than the default? B and C, or reference member of initialization A The most efficient way is to use the following initialization list function try block. It looks like a normal try {..} block, but it does not enter the function body. Instead, it contains a function definition and a list of initialized constructors that associate a series of catch () {} clauses with the whole function body. Even though you can use the function try block with regular functions and destructors, it makes sense to use a constructor with an initialized list. why? We will see it later in the post.

Destructors are also special member functions used in the C ++ programming language. The destructor has the opposite function to the constructor. The main purpose of the destructor is to release dynamically allocated memory. Destructors are used to free memory, free resources, and perform other cleanups. When the object is destroyed, the destructor is automatically named. Like the constructor, use the same name as the class name for the destructor. Member functions can be used (and must also be used) to interact with data contained in user-defined types. User-defined types provide flexibility for "divide-and-conquer" approach in programming. In other words, the programmer can write a user-defined type and guarantee the interface. Another programmer can write the main program using the expected interface. These two parts are gathered and compiled for use. User - defined types provide encapsulation defined in the object - oriented programming (OOP) paradigm.

The destructor method can be defined in any C # class, but the problem with destructors (also known as finalizers in C #) is that you can not determine when to call. They are called by the garbage collector on future uncertainties (called by another thread and other problems may occur). It is not a best practice for C # to try to force garbage collection by using GC.Collect () to resolve these limitations. Block threads for unknown time while collecting all objects that meet the collection criteria.