Question

So I split my files into a few pieces and now i’m getting a bunch of type errors. Such as:

phoneNUmber.h 'istream does not name a type'

What’s this mean exactly? Here’s my files they’re pretty short.

Main

#include <iostream>
#include <fstream>
#include <string>
#include "phoneEntry.h"
using namespace std;

int main()
{   
    PhoneEntry entry;
    ifstream filezilla;
    filezilla.open("phone.txt");

    if(filezilla)
    {
        while(!filezilla.eof() && entry.readEntry(cin))
        {
            entry.writeEntry(cout);
        }
    }
    else
    {
        cout << "Four Oh Four - File Not Found" << endl;
    }

    return 0;
}

Phone Entry

#include "phoneNumber.h"

class PhoneEntry
{
    private: 
        PhoneNumber phone;
        string firstName,
               lastName;
        void _writeDots(ostream& fout, int n) const;
    public:
        istream& readEntry(istream&);
        ostream& writeEntry(ostream&) const;

};

istream& PhoneEntry::readEntry(istream& Sin)                    
{
    Sin >> firstName >> lastName;
    phone.readNumber(Sin);

    return Sin;
};

ostream& PhoneEntry::writeEntry(ostream& Sout) const            
{   
    const int num = 28;
    int fill = num - ((firstName + lastName).length());

    Sout << firstName << ", " << lastName;

    _writeDots(Sout, fill);
    phone.writeNumber(Sout);

    return Sout;
};

void PhoneEntry::_writeDots(ostream& fout, int n) const
{
    if(n % 2)
    {
        fout << ".";
    }

    for(int i = 0; i < n; i++)
    {
        fout << " .";
    }
};

PhoneNumber

class PhoneNumber
{
    private: 
        int areaCode, 
            prefix, 
            suffix;
    public: 
        istream& readNumber(istream&);
        ostream& writeNumber(ostream&) const;
};

istream& PhoneNumber::readNumber(istream& Sin)                  
{
    Sin >> areaCode >> prefix >> suffix;
    return Sin;
};

ostream& PhoneNumber::writeNumber(ostream& Sout) const          
{
    Sout << " " << areaCode << "-" << prefix << "-" << suffix << endl;
    return Sout;
};

Answer 1

What’s this mean exactly?

It means that the compiler thinks ifstream is a variable name, with no associated type. It thinks this, because it hasn’t been given the class definition for ifstream due to you missing the proper include files:

#include <iostream>
#include <fstream>
#include <string>

Additionally, in PhoneEntry.cpp and PhoneNumber.cpp

everyplace you have a istream it should be std::istream

Same with ostream and ifstream etc.

In your main.cpp you have the following statement using namespace std; which imports the std namespace into the global namespace, thus inside that file, you don’t have to prepend the namespace std:: to all the iostream calls.

Since you split things out, each new cpp file no longer has the std:: in it’s global namespace, thus you have to do it yourself.

You could add using namespace std; inside your cpp files, but I usually don’t.