实验四

1.Car

#ifndef BATTERY_H
#define BATTERY_H
class Battery{
public:
    Battery(int size = 70);
    int rebattery();
    int batterySize;
};
#endif

#ifndef CAR_H
#define CAR_H
#include<iostream>
#include<string>
using namespace std;
class Car{
public:
    Car(string maker1,string model1,int year1,int odometer1=0):maker(maker1),model(model1),year(year1),odometer(odometer1){}
    friend ostream& operator<<(ostream &out, const Car &c);
    void updateOdometer(int o2);
    string maker, model;
    int year, odometer;
};
#endif

#ifndef ELECTRICCAR_H
#define ELECTRICCAR_H
#include"battery.h"
#include"car.h"
#include<iostream>
#include<string>
class ElectricCar:public Car, public Battery {
public:
    ElectricCar(string maker2,string model2,int year2,int odometer2=0,int size2=70):Car(maker2,model2,year2,odometer2),Battery(size2){}
    friend ostream& operator<<(ostream &outCar, const ElectricCar &e);
    void updateOdometer(int o2);
};
#endif

#include"battery.h"

Battery::Battery(int size) {
    batterySize = size;
}
int Battery::rebattery() {
    return batterySize;
}

#include"car.h"
#include<string>
#include<iostream>
using namespace std;

ostream& operator<<(ostream &out, const Car &c) {
    out << "maker:" << c.maker << endl << "moder:" << c.model << endl << "year:" << c.year << endl << "odometer:" << c.odometer << endl;
    return out;
}
void Car::updateOdometer(int o2) {
    if (o2 < odometer) cout << "the number is wrong" << endl;
    else odometer = o2;
}

#include"electricCar.h"
#include"battery.h"
#include"car.h"
#include<iostream>
using namespace std;

ostream& operator<<(ostream &out, const ElectricCar &e) {
    out << "maker:" << e.maker << endl << "moder:" << e.model << endl << "year:" << e.year << endl << "odometer:" << e.odometer << endl << "batterySize:" << e.batterySize << endl;
    return out;
}
void ElectricCar::updateOdometer(int o2) {
    if (o2 < odometer) cout << "the number is wrong" << endl;
    else odometer = o2;
}

#include <iostream>
using namespace std;

#include "car.h"
#include "electricCar.h" 

int main() {
    // 测试Car类 
    Car oldcar("Audi", "a4", 2016);
    cout << "--------oldcar's info--------" << endl;
    oldcar.updateOdometer(25000);
    cout << oldcar << endl;

    // 测试ElectricCar类 
    ElectricCar newcar("Tesla", "model s", 2016);
    newcar.updateOdometer(2500);
    cout << "\n--------newcar's info--------\n";
    cout << newcar << endl;

    system("pause");

    return 0;
}

2.Array

#ifndef ARRAY_INT_H
#define ARRAY_INT_H

class ArrayInt{
    public:
        ArrayInt(int n, int value=0);
        ~ArrayInt();
        // 补足:将运算符[]重载为成员函数的声明
        int & operator[](int s);
        void print(); 
    private:
        int *p;
        int size;
};

#endif

#include "arrayInt.h"
#include <iostream>
#include <cstdlib>
using std::cout;
using std::endl;

ArrayInt::ArrayInt(int n, int value): size(n) {
    p = new int[size];
    
    if (p == nullptr) {
        cout << "fail to mallocate memory" << endl;
        exit(0); 
    } 
    
    for(int i=0; i<size; i++)
        p[i] = value;
}

ArrayInt::~ArrayInt() {
    delete[] p;
}

void ArrayInt::print() {
    for(int i=0; i<size; i++)
        cout << p[i] << " ";
    cout << endl;
}

// 补足:将运算符[]重载为成员函数的实现
// ×××
int &ArrayInt::operator [](int s) {
    return p[s];
}

#include <iostream>
using namespace std;

#include "arrayInt.h"

int main() {
    // 定义动态整型数组对象a，包含2个元素，初始值为0
    ArrayInt a(2);
    a.print();
    
    // 定义动态整型数组对象b，包含3个元素，初始值为6
    ArrayInt b(3, 6);
    b.print();

    // 通过对象名和下标方式访问并修改对象元素
    b[0] = 2;
    cout << b[0] << endl;
    b.print();

    system("pause");

    return 0;
}

总结：

1.第二个程序可以用添加现有项添加进去，但第一个程序添加进去后不能用，所以我第一个程序的main是复制黏贴进去的

2.做重载【】运算符的时候不能用private里面的变量，所以我把那些都定义在了public里面