What is the Rule of Three, Five and Zero in C++?

Rule	Meaning
Rule of Zero	Do not write special member functions. Let std::string, vector and smart pointers handle the resources
Rule of Three	If you need a custom destructor, copy constructor or copy assignment, you probably need all three
Rule of Five	Add the move constructor and move assignment to the three

#include <iostream>
#include <string>
#include <vector>

struct Person {                                   // Rule of Zero: no special functions written
    std::string name;
    std::vector<int> scores;
};

int main() {
    Person a{"Riya", {80, 90}};
    Person b = a;                                  // a correct copy, made by the compiler
    Person c = std::move(a);                       // a correct move
    std::cout << b.name << ' ' << b.scores.size() << ' ' << c.name << ' ' << a.name.empty() << '\n';
}

See Move Semantics and the Rule of Five.

• Previous Interview Question
• Next Interview Question

---

Tutorials
No Content Found.

Exercises & Assignments
No Content Found.

Interview Questions & Answers
No Content Found.