cpp-expert

C++ Expert

Expert guidance for modern C++ development including C++20/23 features, STL, templates, memory management, and high-performance programming.

Core Concepts

Modern C++ Features (C++20/23)

• Concepts and constraints
• Ranges and views
• Coroutines
• Modules
• Three-way comparison (spaceship operator)
• std::format
• std::span
• Designated initializers
• consteval and constinit

Memory Management

• RAII (Resource Acquisition Is Initialization)
• Smart pointers (unique_ptr, shared_ptr, weak_ptr)
• Move semantics and perfect forwarding
• Memory allocation strategies
• Custom allocators
• Memory pools

Performance

• Zero-cost abstractions
• Inline optimization
• Template metaprogramming
• Compile-time computation (constexpr)
• Cache-friendly data structures
• SIMD operations

STL Containers

Sequential Containers

#include <vector>
#include <deque>
#include <list>
#include <array>

// vector - dynamic array
std::vector<int> vec = {1, 2, 3, 4, 5};
vec.push_back(6);
vec.emplace_back(7); // Construct in-place
vec.reserve(100); // Pre-allocate capacity

// deque - double-ended queue
std::deque<int> deq = {1, 2, 3};
deq.push_front(0);
deq.push_back(4);

// list - doubly-linked list
std::list<int> lst = {1, 2, 3};
lst.push_front(0);
lst.push_back(4);
lst.remove(2); // Remove all elements with value 2

// array - fixed-size array
std::array<int, 5> arr = {1, 2, 3, 4, 5};

Associative Containers

#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>

// map - ordered key-value pairs
std::map<std::string, int> ages;
ages["Alice"] = 30;
ages["Bob"] = 25;
ages.insert({"Charlie", 35});

// set - ordered unique elements
std::set<int> numbers = {3, 1, 4, 1, 5, 9};
numbers.insert(2);

// unordered_map - hash table
std::unordered_map<std::string, int> hash_map;
hash_map["key"] = 42;

// unordered_set - hash set
std::unordered_set<int> hash_set = {1, 2, 3};

Algorithms

#include <algorithm>
#include <numeric>
#include <vector>

std::vector<int> numbers = {5, 2, 8, 1, 9, 3, 7};

// Sorting
std::sort(numbers.begin(), numbers.end());
std::sort(numbers.begin(), numbers.end(), std::greater<int>());

// Searching
auto it = std::find(numbers.begin(), numbers.end(), 8);
bool found = std::binary_search(numbers.begin(), numbers.end(), 5);

// Transforming
std::vector<int> doubled(numbers.size());
std::transform(numbers.begin(), numbers.end(), doubled.begin(),
    [](int n) { return n * 2; });

// Filtering
std::vector<int> evens;
std::copy_if(numbers.begin(), numbers.end(), std::back_inserter(evens),
    [](int n) { return n % 2 == 0; });

// Accumulate
int sum = std::accumulate(numbers.begin(), numbers.end(), 0);
int product = std::accumulate(numbers.begin(), numbers.end(), 1,
    std::multiplies<int>());

// Partition
auto pivot = std::partition(numbers.begin(), numbers.end(),
    [](int n) { return n < 5; });

// Remove
numbers.erase(std::remove(numbers.begin(), numbers.end(), 5), numbers.end());

// Unique (remove consecutive duplicates)
std::sort(numbers.begin(), numbers.end());
numbers.erase(std::unique(numbers.begin(), numbers.end()), numbers.end());