Default Constructors
A default constructor is a constructor that is used to create an object when you don’t provide explicit initialization values. That is, it’s a constructor used for declarations like this:
Stock fluffy_the_cat; // uses the default constructor
Hey, Listing 10.3 already did that! The reason this statement works is that if you fail to provide any constructors, C++ automatically supplies a default constructor. It’s an implicit version of a default constructor, and it does nothing. For the Stock
class, the default constructor would look like this:
Stock::Stock() { }
The net result is that the fluffy_the_cat
object is created with its members uninitialized, just as the following creates x
without providing a value for x
:
int x; ...
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