C++ Classes/Structures Class basics
Example
A class is a user-defined type. A class is introduced with the class, struct or union keyword. In colloquial usage, the term "class" usually refers only to non-union classes.
A class is a collection of class members, which can be:
- member variables (also called "fields"),
- member functions (also called "methods"),
- member types or typedefs (e.g. "nested classes"),
- member templates (of any kind: variable, function, class or alias template)
The class and struct keywords, called class keys, are largely interchangeable, except that the default access specifier for members and bases is "private" for a class declared with the class key and "public" for a class declared with the struct or union key (cf. Access modifiers).
For example, the following code snippets are identical:
struct Vector
{
int x;
int y;
int z;
};
// are equivalent to
class Vector
{
public:
int x;
int y;
int z;
};
By declaring a class` a new type is added to your program, and it is possible to instantiate objects of that class by
Vector my_vector;
Members of a class are accessed using dot-syntax.
my_vector.x = 10;
my_vector.y = my_vector.x + 1; // my_vector.y = 11;
my_vector.z = my_vector.y - 4; // my:vector.z = 7;
