Contructor you can think as Creator or God
Destructor you can think as destructor or Evil, devil..
but both are required so the system or program works. :)
What are constructor and destructor in c++?
In C++, a **constructor** is a special member function of a class that is used to initialize objects when they are created. It has the same name as the
class, and it does not have any return type (not even `void`). The purpose of a constructor is to set the initial state of an object by initializing its
data members.
Here's an example:
cpp
class Person {
public:
Person(std::string name) : name_(name) {}
private:
std::string name_;
};
int main() {
Person p("John");
return 0;
}In this example, the `Person` constructor takes a `std::string` parameter `name`, and it initializes the `name_` data member of the object with that
value.
A **destructor**, on the other hand, is a special member function of a class that is used to release any resources allocated by an object when it is
destroyed. It has the same name as the class preceded by a tilde (`~`). The purpose of a destructor is to clean up after an object and free any
resources it may have allocated.
Here's an example:
cpp
class File {
public:
File(const std::string& filename) : file_(new std::ifstream(filename)) {}
~File() { delete file_; }
private:
std::ifstream* file_;
};
int main() {
File f("example.txt");
return 0;
}In this example, the `File` destructor deletes the `file_` object when an instance of the class is destroyed.
Some key points about constructors and destructors:
1. **Constructors are used to initialize objects**, while destructors are used to release resources.
2. **Constructors do not have a return type**, while destructors have the same name as the class preceded by a tilde (`~`).
3. **Constructors can be overloaded** (i.e., multiple constructors with different parameters), but they must all have the same name as the class.
4. **Destructors cannot be overloaded**, and there is only one destructor per class.
It's worth noting that C++11 introduced a new feature called **move semantics**, which allows classes to define special member functions for moving
resources between objects, rather than copying them. This can lead to more efficient use of resources in certain situations.