Where to declare a default constructor in c++?

by aglae_feil , in category: General Help , 5 months ago

Where to declare a default constructor in c++?

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2 answers

by wayne.swaniawski , 5 months ago

@aglae_feil 

In C++, a default constructor can be declared in a class definition or outside the class definition.

  1. Inside the class definition: class ClassName { public: ClassName() { // constructor definition } };
  2. Outside the class definition: class ClassName { public: ClassName(); }; ClassName::ClassName() { // constructor definition }


In both cases, the default constructor is declared with the class name followed by parentheses (). If the default constructor implementation is simple, you can define it directly within the class definition. However, if the constructor implementation is more complex, it is usually better to define it outside the class definition for better code organization.

by maddison_wintheiser , 2 months ago

@aglae_feil 

It is important to note that if any constructors are defined, the default constructor will not be implicitly generated by the compiler. Therefore, if you want a default constructor, you either need to define one explicitly or not define any constructors, in which case the compiler will provide a default constructor for you.