Visual Studio 2017 C++ 11 Error

Does Visual Studio 2017 not support C++ 11. When trying to compile code for C++11, it throws an error. This here is the code:

This code works fine and isn't written in C++11.

    #ifndef SALESITEM_H
    #define SALESITEM_H

    // Definition of Sales_item class and related functions goes here


    #include <iostream>
    #include <string>

    class Sales_item {
    friend bool operator==(const Sales_item&, const Sales_item&);
    // other members as before
    public:
        // added constructors to initialize from a string or an istream
        Sales_item(const std::string &book):
                  isbn(book), units_sold(0), revenue(0.0) { }
        Sales_item(std::istream &is) { is >> *this; }
        friend std::istream& operator>>(std::istream&, Sales_item&);
        friend std::ostream& operator<<(std::ostream&, const Sales_item&);
    public:
        // operations on Sales_item objects
        // member binary operator: left-hand operand bound to implicit this pointer
        Sales_item& operator+=(const Sales_item&);
        // other members as before

    public:
        // operations on Sales_item objects
        double avg_price() const;
        bool same_isbn(const Sales_item &rhs) const
            { return isbn == rhs.isbn; }
        // default constructor needed to initialize members of built-in type
        Sales_item(): units_sold(0), revenue(0.0) { }
    // private members as before
    private:
        std::string isbn;
        unsigned units_sold;
        double revenue;

    };


    // nonmember binary operator: must declare a parameter for each operand
    Sales_item operator+(const Sales_item&, const Sales_item&);

    inline bool 
    operator==(const Sales_item &lhs, const Sales_item &rhs)
    {
        // must be made a friend of Sales_item
        return lhs.units_sold == rhs.units_sold &&
               lhs.revenue == rhs.revenue &&
           lhs.same_isbn(rhs);
    }

    inline bool 
    operator!=(const Sales_item &lhs, const Sales_item &rhs)
    {
        return !(lhs == rhs); // != defined in terms of operator==
    }

    using std::istream; using std::ostream;

    // assumes that both objects refer to the same isbn
    inline
    Sales_item& Sales_item::operator+=(const Sales_item& rhs) 
    {
        units_sold += rhs.units_sold; 
        revenue += rhs.revenue; 
        return *this;
    }

    // assumes that both objects refer to the same isbn
    inline
    Sales_item 
    operator+(const Sales_item& lhs, const Sales_item& rhs) 
    {
        Sales_item ret(lhs);  // copy lhs into a local object that we'll return
        ret += rhs;           // add in the contents of rhs 
        return ret;           // return ret by value
    }

    inline
    istream& 
    operator>>(istream& in, Sales_item& s)
    {
        double price;
        in >> s.isbn >> s.units_sold >> price;
        // check that the inputs succeeded
        if (in)
            s.revenue = s.units_sold * price;
        else 
            s = Sales_item();  // input failed: reset object to default state
        return in;
    }

    inline
    ostream& 
    operator<<(ostream& out, const Sales_item& s)
    {
        out << s.isbn << "\t" << s.units_sold << "\t" 
            << s.revenue << "\t" <<  s.avg_price();
        return out;
    }

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


    #endif

When I go for this Code that is C++11, I get an error

    #ifndef SALESITEM_H
    // we're here only if SALESITEM_H has not yet been defined 
    #define SALESITEM_H

    #include "Version_test.h" 

    // Definition of Sales_item class and related functions goes here
    #include <iostream>
    #include <string>

    class Sales_item {
    // these declarations are explained section 7.2.1, p. 270 
    // and 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 are explained in section 7.1.4, pages 262 - 265
        // default constructor needed to initialize members of built-in type
    #if defined(IN_CLASS_INITS) && defined(DEFAULT_FCNS)
        Sales_item() = default;
    #else
        Sales_item(): units_sold(0), revenue(0.0) { }
    #endif
        Sales_item(const std::string &book):
                  bookNo(book), units_sold(0), revenue(0.0) { }
        Sales_item(std::istream &is) { is >> *this; }
    public:
        // operations on Sales_item objects
        // member binary operator: left-hand operand bound to implicit this pointer
        Sales_item& operator+=(const Sales_item&);

        // operations on Sales_item objects
        std::string isbn() const { return bookNo; }
        double avg_price() const;
    // private members as before
    private:
        std::string bookNo;      // implicitly initialized to the empty string
    #ifdef IN_CLASS_INITS
        unsigned units_sold = 0; // explicitly initialized
        double revenue = 0.0;
    #else
        unsigned units_sold;  
        double revenue;       
    #endif
    };

    // used in chapter 10
    inline
    bool compareIsbn(const Sales_item &lhs, const Sales_item &rhs) 
    { return lhs.isbn() == rhs.isbn(); }

    // nonmember binary operator: must declare a parameter for each operand
    Sales_item operator+(const Sales_item&, const Sales_item&);

    inline bool 
    operator==(const Sales_item &lhs, const Sales_item &rhs)
    {
        // must be made a friend of Sales_item
        return lhs.units_sold == rhs.units_sold &&
               lhs.revenue == rhs.revenue &&
               lhs.isbn() == rhs.isbn();
    }

    inline bool 
    operator!=(const Sales_item &lhs, const Sales_item &rhs)
    {
        return !(lhs == rhs); // != defined in terms of operator==
    }

    // assumes that both objects refer to the same ISBN
    Sales_item& Sales_item::operator+=(const Sales_item& rhs) 
    {
        units_sold += rhs.units_sold; 
        revenue += rhs.revenue; 
        return *this;
    }

    // assumes that both objects refer to the same ISBN
    Sales_item 
    operator+(const Sales_item& lhs, const Sales_item& rhs) 
    {
        Sales_item ret(lhs);  // copy (|lhs|) into a local object that we'll return
        ret += rhs;           // add in the contents of (|rhs|) 
        return ret;           // return (|ret|) by value
    }

    std::istream& 
    operator>>(std::istream& in, Sales_item& s)
    {
        double price;
        in >> s.bookNo >> s.units_sold >> price;
        // check that the inputs succeeded
        if (in)
            s.revenue = s.units_sold * price;
        else 
            s = Sales_item();  // input failed: reset object to default state
        return in;
    }

    std::ostream& 
    operator<<(std::ostream& out, const Sales_item& s)
    {
        out << s.isbn() << " " << s.units_sold << " "
            << s.revenue << " " << s.avg_price();
        return out;
    }

    double Sales_item::avg_price() const
    {
        if (units_sold) 
            return revenue/units_sold; 
        else 
            return 0;
    }
    #endif

This code is from C++ Primer 5th edition. The previous one is from the forth edition. The forth edition one(First one) works fine, but the second one throws error.

So, if in case C++11 doen't work with Visual Studio 2017, then how can I enable it.