C++ class using Codeblocks -

i learning c++ through c++ primer book. creating class objects. ireally not know program work. using codeblocks 13.12 , have copy code:

#include <iostream> #include "sales_item.h" int main() {     sales_item book;     //read isbn, number of copies sold, , sales price     std::cin>>book;     //write isbn, number of copies sold, total revenue, , average price     std::cout<<book<<std:endl;     return 0; } 

after there error(i not because there small red square on right of code line: #include "sales_item.h"

i tried created class(the author not ask that) , 2 files created:

sales_item.h.h    #ifndef sales_item_h_h #define sales_item_h_h   class sales_item.h {     public:         sales_item.h();         virtual ~sales_item.h();     protected:     private: };  #endif // sales_item_h_h 

and second one:

sales_item.h.cpp  #include "sales_item.h.h"  sales_item.h::sales_item.h() {     //ctor }  sales_item.h::~sales_item.h() {     //dtor } 

the author asks copy following code current directory. not know means "current directory".

/* file defines sales_item class used in chapter 1. * code used in file explained in * chapter 7 (classes) , chapter 14 (overloaded operators) * readers shouldn't try understand code in file * until have read chapters. */  #ifndef salesitem_h // we're here if salesitem_h has not yet been defined #define salesitem_h  // definition of sales_item class , related functions goes here #include <iostream> #include <string>  class sales_item {     // these declarations explained section 7.2.1, p. 270     // , in chapter 14, pages 557, 558, 561     friend std::istream& operator>>(std::istream&, sales_item&);     friend std::ostream& operator<<(std::ostream&, const sales_item&);     friend bool operator<(const sales_item&, const sales_item&);     friend bool operator==(const sales_item&, const sales_item&); public:     // constructors explained in section 7.1.4, pages 262 - 265     // default constructor needed initialize members of built-in type     sales_item(): units_sold(0), revenue(0.0) { }     sales_item(const std::string &book):     bookno(book), units_sold(0), revenue(0.0) { }     sales_item(std::istream &is) { >> *this; } public:     // operations on sales_item objects     // member binary operator: left-hand operand bound implicit pointer     sales_item& operator+=(const sales_item&);      // operations on sales_item objects     std::string isbn() const { return bookno; }     double avg_price() const; // private members before private:     std::string bookno; // implicitly initialized empty string     unsigned units_sold;     double revenue; }; 

thanks!

the author has "asked" copy code sales_item.h file. please delete own class sales_item.h comprising both files sales_item.h.h , sales_item.h.cpp , start on author's sales_item.h file , create sales_item.cpp if needed.

the class name sales_item, not sales_item.h. current directory means code resides.