#include <iostream>
#include <string>
using namespace std;
class Book {
    char *title;
    char *author;
    int numsold;

public:
    Book() {
    }
    Book(const char *str1, const char *str2, const int num) {
        int len = strlen(str1);
        title = new char[len + 1];
        strcpy(title, str1);
        len = strlen(str2);
        author = new char[len + 1];
        strcpy(author, str2);
        numsold = num;
    }
    void setbook(const char *str1, const char *str2, const int num) {
        int len = strlen(str1);
        title = new char[len + 1];
        strcpy(title, str1);
        len = strlen(str2);
        author = new char[len + 1];
        strcpy(author, str2);
        numsold = num;
    }
    ~Book() {
        delete title;
        delete author;
    }
    void print(ostream &output) {
        output << "book:" << title << endl;
        output << "author:" << author << endl;
        output << "total:" << numsold << endl;
    }
};

int main() {
    Book obj1("Physics", "LiFu", 200), obj2;
    obj1.print(cout);
    obj2.setbook("C++ Programming", "SunJuason", 300);
    obj2.print(cout);
    return 0;
}

/*
book:Physics
author:LiFu
total:200
book:C++ Programming
author:SunJuason
total:300
*/