In C++ , an “`operator`

” is a special function that is used to perform operations on objects.

Operators can be overloaded, which means you can set or redefine the way operators work for user-defined data types.

Let’s see some common examples of operators and how they can be overloaded in C++ !

Arithmetic Operators
Arithmetic operators perform basic mathematical operations.

Example of Addition Operator Overloading (`+`

)

#include <iostream>
class Complex {
public:
real float , image ;
Complex ( float r = 0 , float i = 0 ) : real ( r ), imag ( i ) {}
// Operator overloading +
Complex operator + ( const Complex & obj ) {
return Complex ( real + obj . real , imag + obj . imag );
}
};
int main () {
Complex c1 ( 3.0 , 4.0 ), c2 ( 1.0 , 2.0 );
Complex c3 = c1 + c2 ;
std :: cout << "Result: " << c3 . real << " + " << c3 . imag << "i" << std :: endl ;
return 0 ;
}

Relational Operators
Relational operators compare two values.

Equality Operator Overloading Example (`==`

)

#include <iostream>
class Complex {
public:
real float , image ;
Complex ( float r = 0 , float i = 0 ) : real ( r ), imag ( i ) {}
// Operator overloading ==
bool operator == ( const Complex & obj ) {
return ( real == obj . real && imag == obj . imag );
}
};
int main () {
Complex c1 ( 3.0 , 4.0 ), c2 ( 3.0 , 4.0 );
if ( c1 == c2 ) {
std :: cout << "Complex numbers are equal." << std :: endl ;
} else {
std :: cout << "Complex numbers are different." << std :: endl ;
}
return 0 ;
}

Assignment Operators
Assignment operators assign a value to a variable.

Assignment Operator Overloading Example (`=`

)

#include <iostream>
class Complex {
public:
real float , image ;
Complex ( float r = 0 , float i = 0 ) : real ( r ), imag ( i ) {}
// Operator overloading =
Complex & operator = ( const Complex & obj ) {
if ( this != & obj ) {
real = obj . real ;
imag = obj . imag ;
}
return * this ;
}
};
int main () {
Complex c1 ( 3.0 , 4.0 ), c2 ;
c2 = c1 ;
std :: cout << "c2: " << c2 . real << " + " << c2 . imag << "i" << std :: endl ;
return 0 ;
}

Insertion and Extraction Operators
The insertion (`<<`

) and extraction (`>>`

) operators are used for data input and output.

Example of Insertion Operator Overloading (`<<`

)

#include <iostream>
class Complex {
public:
real float , image ;
Complex ( float r = 0 , float i = 0 ) : real ( r ), imag ( i ) {}
// Operator overloading <<
friend std :: ostream & operator << ( std :: ostream & out , const Complex & obj ) {
out << obj . real << " + " << obj . imag << "i" ;
return out ;
}
};
int main () {
Complex c1 ( 3.0 , 4.0 );
std :: cout << "Complex number: " << c1 << std :: endl ;
return 0 ;
}

Unary Operators
Unary operators operate on a single operand.

Example of Negation Operator Overloading (`-`

)

#include <iostream>
class Complex {
public:
real float , image ;
Complex ( float r = 0 , float i = 0 ) : real ( r ), imag ( i ) {}
// Unary operator overloading -
Complex operator - () const {
return Complex ( - real , - imag );
}
};
int main () {
Complex c1 ( 3.0 , 4.0 );
Complex c2 = - c1 ;
std :: cout << "c2: " << c2 . real << " + " << c2 . imag << "i" << std :: endl ;
return 0 ;
}

These are just some examples of operators in C++ and how they can be overloaded. Operator overloading allows you to define the behavior of operators for custom data types, making your code more intuitive and readable.

Useful links
cpp
cppdaily

Marcos Oliveira
Software developer