Sorting is a common operation in many programming tasks, and C++ provides powerful built-in functions like std::sort to easily sort data. However, in some cases, the default sorting mechanism may not be suitable for custom data types or specific sorting requirements. In such scenarios, using custom sorting literals can be a great solution.
Defining Custom Sorting Criteria
To define custom sorting criteria, you need to provide a function or a lambda expression that compares two elements and returns a boolean value indicating their relative order.
Let’s consider an example where we have a Person class with attributes name and age. We want to sort a vector of Person objects based on their age in ascending order.
#include <iostream>
#include <vector>
#include <algorithm>
class Person {
public:
std::string name;
int age;
};
int main() {
std::vector<Person> people = { {"Alice", 25}, {"Bob", 30}, {"Charlie", 20} };
// Custom sorting criteria based on age
auto sortByAge = [](const Person& a, const Person& b) {
return a.age < b.age;
};
std::sort(people.begin(), people.end(), sortByAge);
// Print sorted people
for (const auto& person : people) {
std::cout << "Name: " << person.name << ", Age: " << person.age << std::endl;
}
return 0;
}
In the code above, we define a lambda expression sortByAge that compares two Person objects based on their age. We pass this lambda expression to std::sort as the custom sorting criteria.
Output
The output of the above code will be:
Name: Charlie, Age: 20
Name: Alice, Age: 25
Name: Bob, Age: 30
As you can see, the vector of Person objects is sorted based on their age in ascending order.
Conclusion
Custom sorting literals in C++ allow you to sort data using custom criteria that go beyond the default comparators. It gives you flexibility and control over how your data should be sorted. By defining custom sorting criteria using functions or lambda expressions, you can customize the sorting process according to your specific needs.
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