Classes and Objects: Static Variables in C++

Static Variables in a Class

• A static variable is used to share a common value among all instances of a class.
• A static variable differs from a non-static variable in that it is shared by all objects of the class, whereas a non-static variable is unique to each object.
• The 'count' variable in the 'item' class is a static variable that keeps track of the total number of items created.

Static Variable as a Counter

• The 'count' variable is used as a counter to keep track of the total number of items created.
• The 'count' variable is updated by the constructor method in the 'item' class.

Static Data Members vs. Static Member Functions

• A static data member is a shared variable that belongs to a class, whereas a static member function is a shared function that belongs to a class.
• Static data members and static member functions are both shared by all objects of the class.

Characteristics of Static Variables

• Static variables are suitable for maintaining values common to the entire class because they are shared by all objects of the class.
• If the 'count' variable in the 'item' class was not declared as static, each object would have its own 'count' variable, and the total number of items created would not be maintained.

Program Illustration

• The 'item' class illustrates the use of a static data member to keep track of the total number of items created.

Learn how static variables are used to maintain values common to the entire class in C++. This program example illustrates the use of a static data member to count occurrences of all the objects.