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C++ - Assignment Operator Overloading

Assignment operator (=) is a binary operator which means it requires two operand to produce a new value. The declaration is identical to any binary operator, with the following exception:

  • It can not be declared as a non-member function. It must be a non-static member function.
  • It is not inherited by derived classes.
  • If operator= is not specified in a class, compiler generates a default operator= and inserts it into the code.

Example: overloading assignment operator

In the example below, assignment operator (=) is overloaded. It is used to assign value from one vector object to another vector object.

#include <iostream>
using namespace std;
class vector {
    float x, y;

    //class constructor
    vector(float x, float y) {
      this->x = x;
      this->y = y;

    //function to display vector
    void displayVector() {
      cout<<"("<<x<<", "<<y<<")\n"; 

    //function for overloading =
    vector operator= (const vector v) {
      this->x = v.x;
      this->y = v.y;  
      return *this;  
int main (){
  vector v1(10, 15), v2(5, 25);
  cout<<"Before assignment:\n"; 
  //using overloaded = operator
  v1 = v2;

  cout<<"\nAfter assignment:\n"; 
  return 0;

The output of the above code will be:

Before assignment:
(10, 15)
(5, 25)

After assignment:
(5, 25)
(5, 25)

❮ C++ - Operator Overloading