Custom Priority Queue (C++)

This project implements a custom generic priority queue container in modern C++, similar to std::priority_queue, with configurable:

• value type
• underlying container
• comparison strategy

It also includes a small demo in main.cpp.

Project Structure

• priority_queue.hpp - declaration of priorityQueue template class and deduction guides
• priority_queue.impl.hpp - implementation of all priorityQueue member functions
• Algorithm.hpp - declarations of heap utility algorithms in namespace Heap
• Algorithm.impl.hpp - implementation of heap algorithms (makeHeap, pushHeap, popHeap, Heapify)
• main.cpp - usage examples and output demo

Architecture

The design is split into two layers:

1. Container layer (priorityQueue)
   • Public API: push, pop, top, empty, size, emplace, swap
   • Owns data (Container c) and comparison object (Compare cmp)
2. Algorithm layer (Heap namespace)
   • Stateless heap procedures that operate on iterator ranges
   • Called internally by priorityQueue to maintain heap invariants

High-Level Flow

• Constructor from container/range -> Heap::makeHeap(...)
• push / emplace -> append element -> Heap::pushHeap(...)
• pop -> Heap::popHeap(...) -> remove last element
• top -> returns c.front() (heap root)

Class and Dependency Diagram

flowchart TD
    A[main.cpp] --> B[priorityQueue<T, Container, Compare>]
    B --> C[Container c]
    B --> D[Compare cmp]

    B --> E[Heap::makeHeap]
    B --> F[Heap::pushHeap]
    B --> G[Heap::popHeap]

    G --> H[Heap::Heapify]
    H --> I[Heap::getLeft]
    H --> J[Heap::getRight]

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Dependency Notes

• priority_queue.hpp includes Algorithm.hpp
• priority_queue.impl.hpp depends on Heap functions declared in Algorithm.hpp
• Algorithm.hpp includes Algorithm.impl.hpp (template implementation pattern)
• main.cpp depends only on priority_queue.hpp (plus standard library headers)

Build and Run

Simple compile command:

g++ main.cpp

Run:

• Linux:

./a.out

• Windows:

./a.exe

Example Usage

priorityQueue<int> maxQ;
maxQ.push(10);
maxQ.push(3);
maxQ.push(7);

std::cout << maxQ.top() << '\n'; // highest-priority element
maxQ.pop();