When working with custom data types in C++, you may encounter the need to sort objects based on a custom ordering. By default, C++ provides sorting functionality for standard data types like integers and strings. However, when it comes to custom types, you need to define your own comparison logic.

In this article, we will explore how to implement custom sorting literals in C++.

Table of Contents

• Defining Custom Sorting Logic
• Using Custom Sorting Literals
• Example: Sorting Custom Objects
• Conclusion

Defining Custom Sorting Logic

To sort custom objects, you need to provide a comparison function that defines the ordering between two objects. C++ provides the std::sort function from the <algorithm> library, which accepts a comparison function as a parameter.

The comparison function takes two objects and returns true if the first object should come before the second object in the sorted order. It returns false otherwise.

bool customComparison(const MyCustomType& obj1, const MyCustomType& obj2) {
    // Define your custom sorting logic here
}

You can define your own logic inside the customComparison function, based on the properties or attributes of your custom type.

Using Custom Sorting Literals

Once you have defined the comparison function, you can use it with the std::sort function to sort a collection of custom objects.

std::vector<MyCustomType> myObjects;
// Add objects to the vector

std::sort(myObjects.begin(), myObjects.end(), customComparison);

By passing the customComparison function as the third argument to std::sort, the objects in myObjects will be sorted according to the custom logic defined in customComparison.

Example: Sorting Custom Objects

Let’s consider an example where we have a custom class Person with name and age attributes. We want to sort a vector of Person objects based on their age in descending order.

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

bool ageDescending(const Person& p1, const Person& p2) {
    return p1.age > p2.age;
}

int main() {
    std::vector<Person> people = {{"Alice", 25}, {"Bob", 23}, {"Charlie", 30}};

    std::sort(people.begin(), people.end(), ageDescending);

    // Print sorted list
    for (const Person& p : people) {
        std::cout << p.name << " - " << p.age << std::endl;
    }

    return 0;
}

The ageDescending function implements the custom sorting logic based on the age attribute of Person objects. By passing ageDescending as the third argument to std::sort, the people vector will be sorted based on age in descending order.

Conclusion

Custom sorting literals in C++ allow you to specify the ordering of elements in a collection of custom objects. By defining a comparison function, you can provide your own logic for sorting based on the attributes or properties of the custom type.

By leveraging the powerful std::sort function from the <algorithm> library, you can easily sort collections of custom objects according to your specific requirements.

Using custom sorting literals empowers you to handle complex sorting scenarios and achieve the desired ordering in your C++ applications.