Comprehensive C++ Interview Preparation: Core Concepts, Syntax, OOP, Memory Management, Algorithms, and Multithreading

Introduction

The article begins with an overview of the significance of C++ in system‑level and application development, especially for AI‑focused companies like iFlytek, and sets the stage for a technical interview.

Process, Thread, and Coroutine

It explains that a process is the basic unit of resource allocation, a thread is the basic unit of CPU scheduling, and a coroutine is a lightweight user‑level thread that runs within a single OS thread.

C++ Operators and Language Features

Differences between new and new[] are described, along with proper use of delete and delete[]. The section also covers static vs const qualifiers, inline functions, and C++20 additions such as concepts, ranges, coroutines, modules, three‑way comparison, calendar support, improved constexpr, and generic lambdas.

C++11 Multithreading

Key components introduced in C++11 are presented: std::thread, join(), detach(), thread IDs, std::mutex, std::lock_guard, condition variables, atomic operations, and utilities in std::this_thread.

Object‑Oriented Programming

The core OOP concepts of encapsulation, inheritance, and polymorphism are discussed, including their benefits for code reuse, safety, and maintainability. Overriding vs overloading, declaration vs definition, and struct vs class differences across C and C++ are also covered.

Memory Management

Virtual memory basics, strategies for detecting and fixing memory leaks, techniques to avoid wild pointers (initialization, nulling after delete, smart pointers, RAII), and alignment rules for efficient data access are explained.

Data Structures and Algorithms

Methods for selecting the top 100 numbers from 10 000 entries are presented (min‑heap, block search, divide‑and‑conquer with hash/Trie), along with time‑complexity analysis of heap sort (stable O(n log n)) and quicksort (average O(n log n), worst‑case O(n²)).

Linked‑List Cycle Detection

The fast‑slow pointer (Floyd’s) algorithm is described, including its O(n) time and O(1) space characteristics, and alternative hash‑based detection.

Multithreading Programming

Thread pools are introduced as a way to reuse threads, manage task queues, adjust pool size based on load, and set thread priorities. The lifecycle of a thread (new, runnable, running, blocked, terminated) and synchronization primitives (mutexes, semaphores, condition variables) are detailed, with guidance on choosing the appropriate mechanism for a given scenario.