What is a constructor chaining in C++?

Constructor chaining, also known as constructor delegation, is a feature in C++ that allows one constructor of a class to call another constructor of the same class to perform common initialization tasks. Constructor chaining simplifies the code and avoids code duplication when multiple constructors need to initialize common data members.

In C++, you can achieve constructor chaining using the member initializer list. The member initializer list is a special syntax used after the constructor's parameter list, where you can specify how the class's data members should be initialized.

The syntax for constructor chaining is as follows:

In this example, we have a class MyClass with multiple constructors, each with different sets of parameters. The constructors with fewer parameters delegate to the constructors with more parameters using the member initializer list. This avoids duplicating the initialization code for the common data members member1 and member2.

Constructor chaining is particularly useful when you have multiple constructors that share similar initialization logic or when you want to provide default values for some constructor parameters. By delegating the constructors, you ensure that the common initialization is done in a single place, improving code maintainability and reducing redundancy.

Please note that constructor chaining is available in C++11 and later versions. Before C++11, you would typically use separate initialization functions to achieve similar functionality, but constructor chaining provides a more elegant and readable solution.