Introduction to the "iff" Operator in C++

What is the "iff" operator?

The "iff" operator in C++ stands for "if and only if". It combines the functionality of the logical "and" and "equal to" operators. It returns true if and only if both operands are true or both operands are false.

The syntax for using the "iff" operator in C++ is:

bool result = expression1 <=> expression2;

When to use the "iff" operator?

The "iff" operator can be used in situations where you want to test if two expressions are equivalent. This can be useful in code where you need to compare two values or evaluate a complex condition.

For example, if you have two integers a and b, you can use the "iff" operator to check if they are equal:

int a = 3;
int b = 3;

bool result = (a <=> b) == 0; // result is true

Other use cases

In addition to comparing values, the "iff" operator can also be used with class types that have overloaded the <=> operator.

For example, if you have two instances of a custom Person class, you can check if they are equal using the "iff" operator:

class Person {
public:
    std::string name;
    int age;

    auto operator<=>(const Person& other) const
    {
        return std::tuple(name, age) <=> std::tuple(other.name, other.age);
    }
};

Person p1 = { "John", 35 };
Person p2 = { "John", 35 };

bool result = (p1 <=> p2) == 0; // result is true

Conclusion

The "iff" operator in C++ provides a concise and intuitive way to test if two expressions are equivalent. Its use can simplify code and make it easier to read and understand.