Overloading Operators in C++

In C++, operators can be overloaded, which means that their behavior can be redefined for specific classes or data types. This allows us to use operators with custom objects in a way that makes sense for our program's logic.

Among the given options (a, b, c, and d), the correct answer is option 'D' (==). The equality operator (==) can be overloaded in C++.

Explanation:

Operator overloading in C++ allows us to redefine the behavior of an operator for a specific class or data type. This means that when the overloaded operator is used with objects or variables of that class or data type, a custom-defined action will be performed.

The equality operator (==) is commonly used to compare the equality of two objects or variables. When used with built-in data types such as integers or floating-point numbers, it simply compares their values. However, when used with objects of a user-defined class, we can define our own criteria for equality.

By overloading the equality operator (==), we can define how two objects of a class should be compared for equality. This allows us to compare objects based on specific attributes or conditions that are meaningful for our program.

For example, let's say we have a class called "Person" with attributes like name and age. By overloading the equality operator (==), we can define that two Person objects are considered equal if their names and ages match.

```cpp
class Person {
public:
string name;
int age;

// Overloading the equality operator
bool operator==(const Person& other) {
return (name == other.name && age == other.age);
}
};

int main() {
Person person1;
person1.name = "John";
person1.age = 25;

Person person2;
person2.name = "John";
person2.age = 30;

if (person1 == person2) {
cout < "both="" persons="" are="" equal."="" />< />
} else {
cout < "persons="" are="" not="" equal."="" />< />
}

return 0;
}
```

In the above example, we have overloaded the equality operator (==) for the Person class. We have defined that two Person objects are considered equal if their names and ages match. In the main function, we create two Person objects with different ages but the same name. When we compare them using the overloaded equality operator, we get the output "Persons are not equal."

To summarize, the equality operator (==) is one of the operators that can be overloaded in C++. By overloading this operator, we can define custom criteria for comparing objects of a class for equality.