What is a class in c plus plus how does it compare with structure in c?

Answer 1

A struct in C is a POD (plain old data) type. A class in C++ can also be a POD for backward compatibility with C code, but more typically combines data with methods that operate upon the data, including constructors and initialisers.

Classes in C++ can be declared using either the struct or class keyword. By convention you will typically use struct to define POD data types and class to define more complex data types.

The only practical difference between a struct and a class is that classes use private access and inheritance by default while struct uses public access and inheritance by default. Thus the following two class definitions are functionally the same:

struct A {

A():m_data(0) {} // public access by default

private:

int m_data;

};

class B {

int m_data; // private access by default

public:

B():m_data(0) {}

};