int main()
{
    cout << "Hello World";    //c-out 输出，相当于printf
    cout << "I am learning C++" << endl; //可以同时输出多个，endl是换行
    return 0;
}

char str[100];
int a;
scanf("%s %d", str, &a);    // 注意，传入的一定是变量的地址

int a;
char str[20];
cin >> a;
cin >> str;

char a;
char str[20];
a = cin.get(); //读取一个字符
cin.get(str, sizeof(str), '\n'); //读取字符串长度的字符数，不包括终止字符（默认是换行符）

string str;
getline(cin, str);

const int myVar  //const常量

int main()
{
    int x;
    cout << "Type a number: ";
    cin >> x;
    cout << "Your number is: " << x;
    return 0;
}

#include <iostream>
using namespace std;

int main()
{
    string food = "Pizza";
    string &meal = food; //取meal的地址指向food的内容\值，类似于快捷方式引用，使得他们都是Pizza

    cout << food << "\n"; //输出Pizza
    cout << meal << "\n"; //输出Pizza
    cout << &food; //输出地址

    return 0;
}

#include <iostream>
using namespace std;

int main()
{
    string food = "Pizza";
    string *ptr = &food; //ptr里面的值是一个内存地址

    cout << food << "\n"; //输出Pizza
    cout << &food << "\n"; //输出地址

    cout << ptr << "\n"; //输出地址
    cout << &ptr << "\n"; //输出地址对应的值

    *ptr = "Hamburger"; //对地址所在的值赋值，即*ptr等效于food
    cout << *ptr << "\n";

    return 0;
}

#include <iostream>
using namespace std;

void myFuction()
{
    cout << "666";
}

int main()
{
    myFuction(); //函数引用
    return 0;
}

//方式一：传指针
template<class T>
void swap1(T *p1,T *p2){
    T temp = *p1; //temp的值为p1所指向的值
    *p1 = *p2;    //*p1的值为p2所指向的值
    *p2 = temp;   //*p2的值为temp所指向的值，即为temp所指向的值p1
}
//测试
int main(){
    int a=10;
    int b=-23;
    swap1(&a,&b); //这就是调用方法的示例
    cout<<a<<","<<b;
    return 0;
}

//方法二，用引用进行交换
template<class T>
void swaps(T &a,T &b){
	T temp = a;
	a = b;
	b = temp;
}
int main(){
	int a=-2;
	int b=16;
	swaps(a,b);
	cout<<a<<endl<<b; //现在a为16,b为-2
	return 0;
}

//方法三，定义宏
#define SWAP2(a,b,temp)((temp)=(a),(a)=(b),(b)=(temp)) //定义宏
int main(){
	int a=15;
	int b=-56
	int temp;
	SWAP2(a,b,temp);   
	cout<<a<<"；"<<b<<endl; //此时的结果为-56；15
}

//方法四，用自带函数
int main(){
	int a,b;
	a = 100;
	b = -200;
	std::swap(a,b);
	cout<<a<<endl<<b; //此时b=100；a=-200
}

#include <iostream>
#include <string>
using namespace std;

class Car
{
public:
    string brand;
    string model;
    int year;
};

int main()
{
    Car carObj1;           // 创造了类的对象（实例），只有在创建实例的时候才真正新生成一个内存块，使用了内存空间
    carObj1.brand = "BWM"; // 给这个对象的brand属性赋值
    carObj1.model = "BWM";
    carObj1.year = 1997;

    cout << carObj1.brand << " " << carObj1.model << " " << carObj1.year; //输出实例的三个属性，用空格作为间隔
    return 0;
}

#include <iostream>
#include <string>
using namespace std;

class Car
{
public:
    int speed(int maxSpeed);
    void myMethod()
    {
        cout << "Hello World!";
    }
};

//方法speed的实现
int Car::speed(int maxSpeed)
{
    return maxSpeed;
}

int main()
{
    Car myObj;           // 创造了类的对象（实例）
    cout << myObj.speed(200) << endl;
    myObj.myMethod(); //调用方法（类中的函数）
    return 0;
}

#include <iostream>
#include <string>
using namespace std;

class Car
{
public:
    string brand;
    string model;
    int year;
    Car(string x, string y, int z);
};

// 构造函数
Car::Car(string x, string y, int z)
{
    brand = x;
    model = y;
    year = z;
}

int main()
{
    Car carObj1("BWM", "XS", 1999);                                       // 直接传入三个参数
    cout << carObj1.brand << " " << carObj1.model << " " << carObj1.year; // 输出实例的三个属性，用空格作为间隔
    return 0;
}

#include <iostream>
using namespace std;

class MyClass
{
    int b;

public:
    int x;
    int y;

private:
    int a;
};

int main()
{
    MyClass myObj;
    myObj.x = 25; // public的x可以访问
    myObj.a = 50; //private的a不能访问，是私有属性
    myObj.b = 11;
    return 0;
}

#include <iostream>
using namespace std;

class Employee
{
private:
    int salary;

public:
    void setSalary(int s)
    {
        salary = s;
    }
    int getSalary()
    {
        return salary;
    }
};

int main()
{
    Employee myObj;
    myObj.setSalary(5000);
    cout << myObj.getSalary();
}

#include <iostream>
using namespace std;

// 父类
class Vehicle
{
public:
    string brand = "Ford";
    void honk()
    {
        cout << "Tuut, tuut! \n";
    }
};

// 子类，继承父类的属性（特性brand，方法honk）
class Car : public Vehicle
{
public:
    string model = "Mustang";
};

int main()
{
    Car myCar; // 创建实例myCar
    myCar.honk();
    cout << myCar.brand + " " + myCar.model;
    return 0;
}

#include <iostream>
using namespace std;

// 基类
class Animal
{
public:
    void animalSound()
    {
        cout << "The animal makes a sound";
    }
};

// 派生类
class Pig : public Animal
{
public:
    void animalSound()
    {
        cout << "The pig says: wee, wee \n";
    }
};

// 派生类
class Dog : public Animal
{
public:
    void animalSound()
    {
        cout << "The pig says: bow, bow \n";
    }
};

int main()
{
    Animal myAnimal;
    Pig myPig;
    Dog myDog;

    myAnimal.animalSound();
    myDog.animalSound();
    myPig.animalSound();
    return 0;
}

#include <iostream>
#include <fstream>
using namespace std;

int main()
{
    // 创建txt
    ofstream MyFile("filename.txt");
    // 写入内容
    MyFile << "Flies can be tricky, but it is fun enough!";
    // 关闭文件
    MyFile.close();

    string myText;                       // 创建一个字符串，用于之后输出文件内容
    ifstream MyReadFile("filename.txt"); // 读取文件

    // 创建一个循环，用于输出一行一行读取的文件内容
    while (getline(MyReadFile, myText))
    {
        cout << myText;
    }
    MyReadFile.close();
}