The & (address) operator yields a pointer to its operand. The operand must be an lvalue, a function designator, or a qualified name. It cannot be a bit field, nor can it have the storage class register.
If the operand is an lvalue or function, the resulting type is a pointer to the expression type. For example, if the expression has type int, the result is a pointer to an object having type int.
If the operand is a qualified name and the member is not static, the result is a pointer to a member of class and has the same type as the member. The result is not an lvalue.
If p_to_y is defined as a pointer to an int and y as an int, the following expression assigns the address of the variable y to the pointer p_to_y :
p_to_y = &y;The ampersand symbol & is used in C++ as a reference declarator in addition to being the address operator. The meanings are related but not identical.
int target;
int &rTarg = target; // rTarg is a reference to an integer.
// The reference is initialized to refer to target.
void f(int*& p); // p is a reference to a pointerIf you take the address of a reference, it returns the address of its target. Using the previous declarations, &rTarg is the same memory address as &target.
You may take the address of a register variable.
You can use the & operator with overloaded functions only in an initialization or assignment where the left side uniquely determines which version of the overloaded function is used.
Related information