Sorting is a fundamental operation in computer programming, and most programming languages provide built-in functions or libraries to sort data. However, sometimes we need to define custom sorting criteria that go beyond the default behavior. In this blog post, we will explore how to perform custom sorting in C++ using literals.

Table of Contents

1. Introduction
2. Custom Sorting
3. Implementing Custom Sorting
4. Example
5. Conclusion

Introduction

By default, C++ provides several sorting algorithms like std::sort in the <algorithm> library, which can sort data based on the default ordering of literals. However, in some cases, we may want to sort data based on our own defined criteria.

Custom Sorting

Custom sorting involves specifying the rules by which data should be sorted. For example, rather than sorting integers in ascending order, we may want to sort them in descending order or according to some other user-defined logic.

In C++, we can achieve this by using a comparison function or a lambda function to define our custom sorting criteria.

Implementing Custom Sorting

To implement custom sorting in C++, we can make use of the std::sort function and provide a comparison function as an argument. The comparison function should take two elements as input and return true if the first element should come before the second element in the sorted order.

Here is the syntax for using the std::sort function with a custom comparison function:

std::sort(begin_iterator, end_iterator, comparison_function);

Alternatively, we can use a lambda function to define the custom sorting criteria inline. Lambda functions are anonymous functions that can be defined at the point of use.

Example

Let’s consider an example where we have a vector of strings and we want to sort them based on their lengths.

#include <algorithm>
#include <iostream>
#include <vector>
#include <string>

int main() {
    std::vector<std::string> names = {"Alice", "Bob", "Charlie", "Dave", "Eve"};

    std::sort(names.begin(), names.end(), [](const std::string& a, const std::string& b) {
        return a.size() < b.size();
    });

    for (const auto& name : names) {
        std::cout << name << std::endl;
    }

    return 0;
}

In this example, we use a lambda function as the comparison function. The lambda function compares the sizes of two strings (a and b) and returns true if the size of a is less than the size of b.

Running this code will sort the names vector based on the lengths of the strings in ascending order.

Conclusion

Custom sorting in C++ allows us to define our own sorting criteria based on specific requirements. By providing a comparison function or a lambda function to the sorting algorithm, we can achieve sorting that goes beyond the default behavior. This feature provides flexibility and enables us to handle various sorting scenarios efficiently.