8 Key Standard Library Algorithms

# Using Subranges vs Iterator Pairs

## What are the use cases for using std::ranges::subrange() versus standard iterator pairs?

Using std::ranges::subrange() and standard iterator pairs both allow you to define a specific portion of a range, but they have different use cases andÂ benefits.

### Iterator Pairs

Iterator pairs have been a traditional way to define subranges in C++. You specify a range by providing two iterators: a beginning and an end. This method is straightforward and has been widelyÂ used:

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

int main() {
std::vector<int> vec{1, 2, 3, 4, 5};

auto begin = vec.begin() + 1;
auto end = vec.begin() + 4;

std::for_each(begin, end, [](int n) {
std::cout << n << ", ";
});
}
2, 3, 4,

### std::ranges::subrange

std::ranges::subrange is part of the C++20 ranges library. It provides a more powerful and expressive way to work with subranges. A subrange is a view that encapsulates a pair of iterators and can be used with range-based algorithmsÂ seamlessly:

#include <algorithm>
#include <iostream>
#include <ranges>
#include <vector>

int main() {
std::vector<int> vec{1, 2, 3, 4, 5};

auto subrange = std::ranges::subrange(
vec.begin() + 1, vec.begin() + 4);

std::ranges::for_each(subrange, [](int n) {
std::cout << n << ", "; });
}
2, 3, 4,

### Benefits ofstd::ranges::subrange

1. Readability: std::ranges::subrange makes the code more readable and expressive, clearly indicating that you are working with a subrange of a collection.
2. Range-based Algorithms: It integrates seamlessly with range-based algorithms and views, making it more flexible and powerful.
3. Type Safety: Provides better type safety and prevents common iterator mistakes.

### Use Cases

Iterator Pairs is suitedÂ for:

• Simple cases where defining the range with iterators is sufficient.
• When working with older codebases that do not use the C++20 ranges library.
• Performance-critical sections where the minimal overhead of raw iterators is beneficial.

std::ranges::subrange is suitedÂ for:

• Modern C++ projects that leverage the power of the ranges library.
• Complex operations involving multiple range-based algorithms and views.
• Codebases where readability, maintainability, and expressiveness are prioritized.

In summary, std::ranges::subrange offers a modern and powerful alternative to iterator pairs, enhancing code readability and integration with range-basedÂ algorithms.

However, iterator pairs remain a valid and useful tool, especially in simpler or performance-criticalÂ contexts.

This Question is from the Lesson:

### 8 Key Standard Library Algorithms

An introduction to 8 more useful algorithms from the standard library, and how we can use them alongside views, projections, and other techniques

Answers to questions are automatically generated and may not have been reviewed.

This Question is from the Lesson:

### 8 Key Standard Library Algorithms

An introduction to 8 more useful algorithms from the standard library, and how we can use them alongside views, projections, and other techniques

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