dot (.) operator in C++ (original) (raw)

Last Updated : 25 Sep, 2024

The **C++ **dot (.) operator is used for **direct member selection via the name of variables of type **class, struct, and union. It is also known as the direct member access operator. It is a binary operator that helps us to extract the value of the function associated with a particular object, structure, or union.

**Syntax:

variable_name.member;

• **variable_name: It's an instance of a class, structure, or union.
• **member: member variables or member functions associated with the created object, structure, or union.

**Example:

C++ `

// C++ Program to demonstrate the use of dot operator #include using namespace std;

class base { public: int var1;

base(int x) { var1 = x; }

void getValue()
{
    cout << "Member Function Called" << endl;
}

};

// driver code int main() { // creating new object base b(222); // calling member function using dot(.) operator b.getValue(); // getting member variable cout << "Member Variable Value: " << b.var1; return 0; }

`

Output

Member Function Called Member Variable Value: 222

C++ `

// C++ Function // tO demonstrate // Indirect member selection operator void addXtoList(Node* node, int x) { // Node is a class

while (node != NULL) {
    node->data = node->data + x;
    node = node->next;
}

}

`

Can the dot (.) operator be overloaded?

No, the dot (.) operator cannot be overloaded in C++. Doing so will cause an error.

**Example:

C++ `

// C++ program // illustrate Overloading // .(dot) operator

#include ; using namespace std;

class cantover { public: void fun(); };

// assume that you can overload . operator // Class X below overloads the . operator class X {

cantover* p;

// Overloading the . operator
cantover& operator.() { return *p; }

void fun();

};

void g(X& x) {

// Now trying to access the fun() method
// using the . operator
// But this will throw an error
// as we have overloaded the . operator above
// Hence compiler won't allow doing so
x.fun();

}

`

**Output:

prog.cpp:11:20: error: expected type-specifier before '.' token
cantover& operator.()
^
prog.cpp:11:12: error: expected ';' at end of member declaration
cantover& operator.()
^
prog.cpp:11:20: error: expected unqualified-id before '.' token
cantover& operator.()
^
prog.cpp: In function 'void g(X&)':
prog.cpp:15:7: error: 'void X::fun()' is private
void fun();
^
prog.cpp:19:8: error: within this context
x.fun(); // X::fun or cantover::fun or error?
^