Colin.cpp
Custom set literals in C++

In C++, the Standard Template Library (STL) provides the std::set container to store unique elements in a sorted manner. However, inserting elements into a std::set requires specifying each element individually using its insert() function. This can be tedious, especially when you have a large number of elements.

To address this inconvenience, C++11 introduced custom set literals. This feature allows you to define your own syntax for creating and initializing sets more easily. Let’s explore how custom set literals work in C++.

Basic Syntax

The syntax for creating a custom set literal in C++ looks like the following:

operator"" _s(...parameters...) { ...literal code... }

Here, operator"" is the operator that enables custom literals, and _s is the suffix indicating that it is a set literal. You can replace _s with any other identifier of your choice.

Example Usage

Suppose we want to create a set literal for integers. We can define the following operator:

std::set<int> operator"" _s(const char* str, size_t len) {
  std::set<int> result;
  // Parse the input string and populate the set
  // with the extracted integers
  // ...
  return result;
}

Now, we can use the set literal as follows:

auto mySet = "1 2 3 4 5 6"_s;

In this example, the string "1 2 3 4 5 6" is passed to the operator"" _s function, which extracts the integers and creates a set containing them. The resulting set is then assigned to the mySet variable.

Benefits of Custom Set Literals

Custom set literals provide several benefits:

  1. Concise Syntax: With custom set literals, you can represent sets in a more concise and intuitive way, avoiding the individual insertion of each element.

  2. Improved Readability: The use of custom set literals enhances code readability by reducing the clutter and noise associated with manually inserting every element.

  3. Flexible Initialization: Custom set literals allow you to initialize sets with different sets of values, making it convenient to work with predefined or dynamic data.

Conclusion

Custom set literals are a powerful feature in C++ that simplify the creation and initialization of sets. This feature streamlines the process of populating set containers with elements, making your code shorter, more expressive, and easier to read. By leveraging custom set literals, you can improve the efficiency and maintainability of your C++ code.

References:

© 2018 Colin. All rights reserved.