C++ oop

1.

#include <iostream>
using namespace std;
class Car
{
        public:
                void display()
                {
                        cout << "This car's color is black!" << endl;
                }
        private:
                int price;
                string color;
};
int main(int argc,char **argv)
{
        Car c;
        c.display();

        Car *c2 = new Car;
        c2->display();
        return 0;
}

#include <string>
#include <fstream>
using namespace std;
int main()
{
        ifstream ifs("hello.txt");
        string s;
        ifs >> s;
        string st;
        ifs >> st;
        cout << s <<", " << st <<endl;
        ifs.close();
        return 0;
}

2.

#include <iostream>
using namespace std;
class Car
{
        public:
                void display();
                void init(string,string);
        private:
                string name;
                string color;
};
        void Car::init(string name,string color)
        {
                this->name = name;
                this->color = color;
        }
        void Car::display()
        {
                cout << "The car name is : " << name << ", " << "Color is : " << color << endl;
        }
int main(int argc,char **argv)
{
        Car *c = new Car;
        c->init("Fold","Black");
        c->display();
}

静态属性

class Car {
    public:
    static int id;
    ...
};
int Car::id = 10;

int main(){
    Car::id = 12;    //使用
}

静态函数
class Car {
    public:
    static int id;
    static void display();
};
int Car:: id = 22;
void Car::display()
{
    cout << "id is : " << id << endl;
}

int main()
{
    Car::id = 10;
    Car::display();
}

带构造函数的类

#include <iostream>
using namespace std;
class Car
{
        public:
        Car(string,string); //declare constructor
        void display();
        private:
        string name;
        string color;
};

Car::Car(string name,string color) //definition constructor
{
        this->name = name;
        this->color = color;
}

void Car::display()
{
        cout << "Name is : " << name << ", " << "Color is : " << color << endl;
}

int main(int argc,char **argv)
{
        Car *c = new Car("Toyota","Black");
        c->display();
}

C++中对文件的操作

#include <iostream>
#include <string>
#include <fstream>
using namespace std;
int  main()
{
        ofstream ofs("hello.txt");
        ofs << "hello linux" << endl;
        ofs << "C++ is very good!" << endl;
        ofs.close();
        return 0;
}

#include <string>
#include <fstream>
using namespace std;
int main()
{
        ifstream ifs("hello.txt");
        string s;
        ifs >> s;
        string st;
        ifs >> st;
        cout << s <<", " << st <<endl;
        ifs.close();
        return 0;
}