What is the meaning of & in c++?

Question

I want to know the meaning of & in the example below:

class1 &class1::instance(){

///something to do

}

Solution 1

This means your method returns a reference to a method1 object. A reference is just like a pointer in that it refers to the object rather than being a copy of it, but the difference with a pointer is that references:

• can never be undefined / NULL
• you can't do pointer arithmetic with them

So they are a sort of light, safer version of pointers.

Solution 2

The & operator has three meanings in C++.

• "Bitwise AND", e.g. 2 & 1 == 3
• "Address-of", e.g.: int x = 3; int* ptr = &x;
• Reference type modifier, e.g. int x = 3; int& ref = x;

Here you have a reference type modifier. Your function class1 &class1::instance() is a member function of type class1 called instance, that returns a reference-to-class1. You can see this more clearly if you write class1& class1::instance() (which is equivalent to your compiler).

Solution 3

Its a reference (not using pointer arithmetic to achieve it) to an object.

Solution 4

It returns a reference to an object of the type on which it was defined.

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