//
// Created by andrew on 2021年5月23日.
//
#include <iostream>
#include <array>

using namespace std;
/*
 * 1. const成员函数不能修改成员变量
 * 2. const对象不能引用非const成员函数
 * */

class WatchData {
public:
 WatchData() = default;
 ~WatchData() = default;

 virtual int GetData() const {
 return m_index;
 }
 // 函数后面的const是修饰所有的成员变量在该函数中为const
 /*void SetData(int &&idx) const { // error: assignment of member ‘WatchData::m_index’ in read-only object
 m_index = idx;
 }*/

 virtual void SetData(int &&idx) {
 m_index = idx;
 }

private:
 int m_index{};
};

class StandData : public WatchData {
public:
 StandData() = default;
 ~StandData() = default;
 int GetData() const override {
 return m_index;
 }
 // 函数后面的const是修饰所有的成员变量在该函数中为const
 /*void SetData(int &&idx) const { // error: assignment of member ‘WatchData::m_index’ in read-only object
 m_index = idx;
 }*/

 void SetData(int &&idx) override {
 m_index = idx;
 }

private:
 int m_index{};
};


void ArrayTest() {
 std::array<char, 100> address{};

 int i = 0;
 for (auto &it : address) {
 it = i;
 i ++;
 }

 std::array<char, 100> address2{};
 std::swap(address,address2);

}


int main(int argc, const char** argv) {

 WatchData watchData{};
 watchData.SetData(6);
 cout << watchData.GetData() << endl;

 // const 对象不能引用非const的成员函数
// const WatchData *pWatchData = &watchData;
 // pWatchData->SetData(4); error: passing ‘const WatchData’ as ‘this’ argument discards qualifiers [-fpermissive]

 StandData standData{};
 standData.WatchData::SetData(43);
 cout << standData.WatchData::GetData() << endl;

 ArrayTest();

 cout << "test" << endl;
 return 0;
}