Question

i have a complex function definition written in c++. It is the first time i have come across such a complex function definition and i am having trouble understanding the meaning of it.

Here it is

t_group& t_group::operator=(const t_group &a)
{

}

specifically i need to know what

operator=(const t_group &a)

mean ?

Answer 1

Here’s the breakdown:

t_group&

The function returns a reference to a t_group.

t_group::

The function is in the t_group namespace. Since t_group is the name of a struct, union, or class, it is a member of t_group.

operator=

The function is an overload of the = operator. Since it is a method, the object is the left-hand-side of the = operator.

(const t_group &a)

This is the parameter to the function: it’s the right-hand-side of the = operator. This says the right-hand-side is a const reference to a t_group, which means the function will not alter the t_group.

Taken together, this is the copy assignment operation for the t_group class. It is invoked by code like:

t_group a, b;
b = a;

The latter line is equivalent to b.operator=(a);.

P.S. assignment operator functions typically end with return *this;. This is so you can chain the assignments (e.g. a = b = c) just like the regular = operator.