Comparing Copy Constructors with Move Constructors - C++ Class

C++ examples for Class:Constructor

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Description

Comparing Copy Constructors with Move Constructors

Demo Code

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

using namespace std;
using namespace chrono;
using namespace literals;

class MyClass/*ww w  . j  av a2 s  . co m*/
{
private:
    vector<string> m_String{" copy constructed!"s};

    int m_Value{ 1 };
public:
    MyClass() = default;
    MyClass(const MyClass& rhs) = default;
    MyClass(MyClass&& rhs) = default;

    int GetValue() const
    {
        return m_Value;
    }
};

int main()
{
    using MyVector = vector<MyClass>;
    constexpr unsigned int ITERATIONS{ 1000000U };

    MyVector copyConstructed(ITERATIONS);
    int value{ 0 };

    auto copyStartTime = high_resolution_clock::now();
    for (unsigned int i=0; i < ITERATIONS; ++i)
    {
        MyClass myClass;
        copyConstructed.push_back(myClass);
        value = myClass.GetValue();
    }
    auto copyEndTime = high_resolution_clock::now();

    MyVector moveConstructed(ITERATIONS);

    auto moveStartTime = high_resolution_clock::now();
    for (unsigned int i=0; i < ITERATIONS; ++i)
    {
        MyClass myClass;
        moveConstructed.push_back(move(myClass));
        value = myClass.GetValue();
    }
    auto moveEndTime = high_resolution_clock::now();

    cout << value << endl;

    auto copyDuration = duration_cast<milliseconds>(copyEndTime - copyStartTime);
    cout << "Copy lasted: " << copyDuration.count() << "ms" << endl;

    auto moveDuration = duration_cast<milliseconds>(moveEndTime - moveStartTime);
    cout << "Move lasted: " << moveDuration.count() << "ms" << endl;

    return 0;
}

Result


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