constructor.cpp

constructor.cpp

//
//  constructor.cpp
//  CplusplusPractice
//
//  Created by masai on 2015/05/22.
//  Copyright (c) 2015年 masai. All rights reserved.
//

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

class constructor_init{
public:
    constructor_init() : m_int(0), m_double(.1), m_str("abc"){}

private:
    int m_int;
    double m_double;
    std::string m_str;
};

class constructor_noninit{
public:
    constructor_noninit(){
        m_int = 0;
        m_double = 0;
        m_str = "abc";
    }
private:
    int m_int;
    double m_double;
    std::string m_str;
};

class parent {
public:
    parent(int a){
        m_int = a;
    }
public:
    int m_int;
};

class child : public parent{
public:
    child() : parent(2){
        
    }
};

void init(bool constinit){
    const auto startTime = std::chrono::system_clock::now();
    
    for(unsigned int i = 0; i < 100000000; ++i){
        if(constinit){
            constructor_init* c = new constructor_init();
        }else{
            constructor_noninit* c = new constructor_noninit();
        }
    }
    
    const auto endTime = std::chrono::system_clock::now();
    const auto duration = endTime - startTime;
    const auto msec = std::chrono::duration_cast<std::chrono::milliseconds>(duration).count();
    
    std::cout << "duration: " << msec << std::endl;
}

int main(){
    // 親クラスの初期化
    child* obj = new child();
    std:: cout << obj->m_int << std::endl;
    
    // コンストラクタ初期を使用した場合と代入の速度比較
    init(true);
    init(false);
}