C++Primer(第七章课后习题程序题源代码）

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

int main()
{
cout << "请输入交易记录(ISBN，销售量，原价，实际售价):" << endl;
Sales_data total;
if (cin >> total)
{
Sales_data trans;
while (cin >> trans)
{
if (total.isbn() == trans.isbn())
total += trans;
else
{
cout << total << endl;
total = trans;
}
}
cout << total << endl;
}
else
{
cerr << "No data?!" << endl;
return -1;
}
return 0;
}

class Sales_data
{
private:
string bookNo;
unsigned units_sold = 0;
double sellingprice = 0.0;
double saleprice = 0.0;
double discount = 0.0;
public:
string isbn() const{ return bookNo; }
Sales_data & combine(const Sales_data &rhs)
{
units_sold += rhs.units_sold;
saleprice = (rhs.saleprice*rhs.units_sold + saleprice*units_sold) / (rhs.units_sold + units_sold);
if (sellingprice != 0)
discount = saleprice / sellingprice;
return *this;
}
};

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

int main()
{
cout << "请输入交易记录(ISBN，销售量，原价，实际售价):" << endl;
Sales_data total;
if (cin >> total)
{
Sales_data trans;
while (cin >> trans)
{
if (total.isbn() == trans.isbn())
total.combine(trans);
else
{
cout << total << endl;
total = trans;
}
}
cout << total << endl;
}
else
{
cerr << "No data?!" << endl;
return -1;
}
return 0;
}

class Person
{
private:
string strName;
string strAddress;
public:
string getName() const{ return strName; }
string getAddress() const{ return strAddress; }
};

Sales_data add(const Sales_data &lhs, const Sales_data &rhs)
{
Sales_data sum = lhs;
sum.combine(rhs);
return sum;
}

std::istream &read(std::istream &is, Sales_data &item)
{
is >> item.bookNo >> item.units_sold >> item.sellingprice >> item.saleprice;
return is;
}

std::ostream &print(std::ostream &os, const Sales_data &item)
{
os << item.isbn() << " " << item.units_sold << " " << item.Sellingprice << " " << item.saleprice << " " << item.discount;
return os;
}

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

int main()
{
cout << "请输入交易记录(ISBN，销售量，原价，实际售价):" << endl;
Sales_data total;
if (read(cin,total))
{
Sales_data trans;
while (read(cin,trans))
{
if (total.isbn() == trans.isbn())
total += trans;
else
{
print(cout, total);
cout << endl;
total = trans;
}
}
print(cout, total);
cout << endl;
}
else
{
cerr << "No data?!" << endl;
return -1;
}
return 0;
}

std::istream& read(std::istream &is, Person &per)
{
is >> per.strName >> per.strAddress;
return is;
}
std::ostream& print(std::ostream &os, const Person &per)
{
os << per.getName() << per.getAddress();
return os;
}

class Screen
{
private:
unsigned height = 0; width = 0;
unsigned cursor = 0;
string contents;
public :
Screen() = default;
Screen(unsigned ht, unsigned wd) :height(ht), width(wd), contents(ht *wd ,' '){ };
Screen(unsigned ht,unsigned wd,char c)
:height(ht), width(wd), contents(ht *wd, c){ }
};

class Sales_data
{
public:
double avg_price() const
{
if (units_sold)
return revenue / units_sold;
else
return 0;
}
};

class Sales_data
{
double avg_price() const
}
inline double Sales_data::avg_price() const
{
if (units_sold)
return revenue / units_sold;
else
return 0;
}

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

class Window_mgr
{
public:
void clear();
};
class Screen
{
friend void Window_mgr::clear();
private:
unsigned height = 0, width = 0;
unsigned cursor = 0;
string contents;
public:
Screen() = default;
Screen(unsigned ht, unsigned wd, char c)
:height(ht), width(wd), contents(ht*wd, c);
};
void Window_mgr::clear();
{
Screen myScreen(10, 20, 'X');
cout << "清理之前myScrenn的内容是："<<endl;
cout << myScreen.contexts << endl;
myScreen.contexts << endl;
cout << myScrean.contents = " ";
cout << 清理之后myScreen的内容是 << endl;
cout << my.Screen.contexts << endl;

}

int main()
{
Window.mgr w;
w.clear();
return 0;
}

class Book
{
private:
string Name, ISBN, Author, Publisher;
double Price = 0;
public:
Book() = default;
Book(const string &n, const string &I, double pr, const string &a, const string &p)
{
Name = n;
ISBN = I;
Price = pr;
Author = a;
Publisher = p;
}
Book(std::istream &is){
is >> *this;
}
};

class Tree
{
private:
string Name;
unsigned Age = 0;
double Height = 0;
public:
Tree() = default;
Tree(const string &n, unsigned a, double h) :Name(n), Age(a), Height(h);
};

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

class Sales_data{
friend std::istream &read(std::istream &is, Sales_data &item);
friend std::ostream &print(std::ostream &os, const Sales_data &item);
public:
Sales_data(const string &book, unsigned num, double sellp, double salep) :
bookNo(book), units_sold(num), sellingprice(sellp), saleprice(salep)
{
if (sellingprice)
discount = saleprice = sellingprice;
cout << "该构造函数接受书号，销售量，原价，实际售价四个信息" << endl;
}
Sales_data() :Sales_data("", 0, 0, 0)
{
cout << "该构造函数无须接受任何信息" << endl;
}
Sales_data(const string &book) :Sales_data(book, 0, 0, 0)
{
cout << "该构造函数接受书号信息" << endl;
}
Sales_data(std::istream &is) :Sales_data()
{
read(is, *this);
cout << "该构造函数接受用户输入的信息" << endl;
}
public :
std::string bookNo;
unsigned units_sold = 0;
double sellingprice = 0.0;
double saleprice = 0.0;
double discount = 0.0;
};

std::istream &read(std::istream &is, Sales_data &item)
{
is >> item.bookNo >> item.units_sold >> item.sellingprice >> item.saleprice;
return is;
}

std::ostream &print(std::ostream &os, Sales_data &item)
{
os << item.bookNo << "" << item.units_sold << " " << item.sellingprice << " " << item.saleprice << " " << item.discount;
return os;
}

int main()
{
Sales_data first("978-7-121-15535-2", 85, 128, 109);
Sales_data second;
Sales_data third("978-7-121-15535-2");
Sales_data last(cin);
return 0;
}

class Book
{
private:
string Name, ISBN, Author, Publisher;
double price = 0;
public:
Book(const string&n, const string &I, double pr, const string &a, const string &p)
:Name(n), ISBN(I), Price(pr), Author(a), Publisher(p){}
Book() :Book("", "", 0, "", ""){}
Book(std::istream &is) :Book(){ is >> *this; }
};

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

class NoDefault
{
public:
NoDefault(int i)
{
val = i;
}
int val;
};

class C
{
public :
NoDefault nd;
C(int i = 0) :nd(i){}
};

int main()
{
C c;
cout <<c.nd.val << endl;
return 0;
}