Ranges Basics

Introduction to the ranges library and range-based algorithms

Example Code

cpp

#include <ranges>
#include <vector>
#include <iostream>
#include <algorithm>
int main() {
    std::vector<int> numbers = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
    
    // Traditional algorithm
    std::vector<int> result1;
    std::copy_if(numbers.begin(), numbers.end(),
                 std::back_inserter(result1),
                 [](int n) { return n % 2 == 0; });
    
    // Range-based algorithm - cleaner syntax
    auto result2 = numbers 
        | std::views::filter([](int n) { return n % 2 == 0; });
    
    std::cout << "Even numbers: ";
    for (int n : result2) {
        std::cout << n << " ";
    }
    std::cout << std::endl;  // Output: 2 4 6 8 10
    
    return 0;
}

Explanation

Ranges provide a more composable and readable way to work with sequences. The pipe operator (|) allows chaining operations, and views are lazy - they don't create intermediate containers.

Key Points

1Ranges work directly on containers
2Pipe operator (|) chains operations
3Views are lazy - computed on demand
4No intermediate containers needed