C++primer 7.1.3 sessions

Exercise 7.6

1#include <iostream>2#include <string>3#include"Factmain.h"4 using namespacestd;5 6 structSales_data {7     stringISBN ()Const{returnBookno;}8Sales_data &combine (Constsales_data&);9     stringBookno;Ten unsigned units_sold; One     DoublePrice =0.0; A     DoubleRevenue =0.0; - }; -  theSales_data Add (ConstSales_data &AMP;LHS,ConstSales_data &RHS); -Ostream &print (Ostream &os,ConstSales_data &item); -IStream &read (IStream & is, Sales_data &item); -  +  - intMain () + { A Sales_data item1, item2; at     DoubleTotalrevenue =0; -     DoubleTotalsold =0; -     intCounter =1; -     if(Read (CIN, item1)) -     { -Item1.revenue = Item1.price *Item1.units_sold; in          while(Read (cin,item2)) { -Item2.revenue = Item2.price *Item2.units_sold; to             if(Item1.bookno = =item2.bookno) { + Item1.combine (item2); -++counter; the             } *             Else { $Print (cout, item1) <<Endl;Panax NotoginsengItem1.bookno =Item2.bookno; -Item1.units_sold =Item2.units_sold; theItem1.revenue =item2.revenue; +Counter =1; A             } the         } +Print (cout, item2) <<Endl; -     } $     return 0; $ } -  -Sales_data Add (ConstSales_data & LHS,ConstSales_data & RHS)//non-member function add the { -Sales_data sum =LHS;Wuyi Sum.combine (RHS); the     returnsum; -     //TODO: Insert a return statement here Wu } -  AboutIStream & Read (IStream & is, Sales_data &Item) $ { -      is>> item.bookno >> item.units_sold >>Item.price; -Item.revenue = Item.units_sold *Item.price; -     return  is; A     //TODO: Insert a return statement here + } the  -Ostream & Print (Ostream & OS,ConstSales_data &Item) $ { theOS << item.bookno <<" "<< Item.units_sold <<" "<< Item.price <<" "<<item.revenue; the     returnos; the     //TODO: Insert a return statement here the } -  inSales_data & Sales_data::combine (ConstSales_data &RHS) the { theUnits_sold + =Rhs.units_sold; AboutRevenue + =rhs.revenue; the     return* This; the}

Exercise 7.7

See above

Exercise 7.8

Read involves the calculation of revenue, Item.revenue is updated, so it is defined as a normal reference, and print is the value of the output object, so it can be declared as a constant reference;

Exercise 7.9

See the procedure at the end of this chapter.

Exercise 7.10

Determine whether the input of data1 and data2 is correct (non-null or input error), first input data1, in the input data2;

C++primer 7.1.3 sessions