How To Use the Sort function in C++?

Sorting is a fundamental operation in computer science and programming. It involves arranging a collection of elements in a specific order. The sort function in C++ is a powerful tool that simplifies the process of sorting arrays, vectors, and other containers.

This guide will explore how to use the sort function effectively with various examples.

1. Sorting Arrays
2. Sorting Vectors
3. Sorting User-Defined Objects
4. Custom Sorting Order

Introduction to the Sort Function in C++

The sort function in C++ is the part of Standard Library and is defined in the <algorithm> header. It provides an easy way to sort elements in ascending order by default. The function can be used with various types of containers, including arrays, vectors, and lists. Additionally, the sort function can take advantage of the comparison operators (<, >, <=, >=, ==, !=) to determine the sorting order.

Sorting Arrays

Arrays are a fixed-size collection of elements. To sort an array using the sort function, follow these steps:

#include <algorithm>
#include <iostream>
int main() {
    int arr[] = {5, 2, 8, 1, 3};
    int size = sizeof(arr) / sizeof(arr[0]);
    std::sort(arr, arr + size);
    std::cout << "Sorted array: ";
    for (int i = 0; i < size; ++i) {
        std::cout << arr[i] << " ";
    }
    return 0;
}

Output

Sorted array: 1 2 3 5 8

Sorting Vectors

Vectors are dynamic arrays that can grow or shrink in size. Sorting a vector is similar to sorting an array:

#include <algorithm>
#include <iostream>
#include <vector>
int main() {
    std::vector<int> vec = {5, 2, 8, 1, 3};
    std::sort(vec.begin(), vec.end());
    std::cout << "Sorted vector: ";
    for (const auto& num : vec) {
        std::cout << num << " ";
    }
    return 0;
}

Output

Sorted vector: 1 2 3 5 8

Sorting User-Defined Objects

You can also sort collections of user-defined objects. In this example, let’s sort a collection of Person objects based on their ages:

#include <algorithm>
#include <iostream>
#include <vector>
#include <string>
struct Person {
    std::string name;
    int age;
};
bool compareByAge(const Person& a, const Person& b) {
    return a.age < b.age;
}
int main() {
    std::vector<Person> people = {
        {"Alice", 25},
        {"Bob", 30},
        {"Eve", 22}
    };
    std::sort(people.begin(), people.end(), compareByAge);
    std::cout << "Sorted by age:\n";
    for (const auto& person : people) {
        std::cout << person.name << " (" << person.age << ")\n";
    }
    return 0;
}

Output

Sorted by age:
Eve (22)
Alice (25)
Bob (30)

Custom Sorting Order

The sort function’s default behavior is to sort elements in ascending order. However, you can specify a custom sorting order using a custom comparator function. In this example, we’ll sort integers in descending order:

#include <algorithm>
#include <iostream>
#include <vector>
bool compareDescending(int a, int b) {
    return a > b;
}
int main() {
    std::vector<int> nums = {5, 2, 8, 1, 3};
    std::sort(nums.begin(), nums.end(), compareDescending);
    std::cout << "Sorted in descending order: ";
    for (const auto& num : nums) {
        std::cout << num << " ";
    }
    return 0;
}

Output

Sorted in descending order: 8 5 3 2 1

Conclusion

The sort function in C++ is a versatile tool for sorting various types of containers.

Whether you’re dealing with arrays, vectors, or user-defined objects, the sort function simplifies arranging elements in a desired order. By using custom comparator functions, you can achieve complex sorting requirements. Incorporate the sort function into your programming toolkit to organize data in your C++ applications efficiently.

This guide covered the basics of using the sort function with examples ranging from simple arrays to custom sorting orders. By mastering this function, you’ll be well-equipped to handle various sorting tasks in your C++ projects.