can not compile C++ constructor

Question

Can anyone please explain to me whats wrong with this piece of code and how to fix it? this is part of a bigger project if you need more information in order to give an anwer please let me know.

the error that im getting is this:

  g++ -c search.cpp
    search.cpp: In constructor ‘Search::Search()’:
    search.cpp:26:26: error: ‘callnumber’ was not declared in this scope
    make: *** [search.o] Error 1



Search::Search()
        {
            ifstream input;
            input.open("data.txt", ios::in);

            if(!input.good())
                //return 1;
            string callnumber;
            string title;
            string subject;
            string author;
            string description;
            string publisher;
            string city;
            string year;
            string series;
            string notes;

            while(! getline(input, callnumber, '|').eof())
            {   
                getline(input, title, '|');
                getline(input, subject, '|');
                getline(input, author, '|');
                getline(input, description, '|');
                getline(input, publisher, '|');
                getline(input, city, '|');
                getline(input, year, '|');
                getline(input, series, '|');
                getline(input, notes, '|');


            Book *book = new Book(callnumber, title, subject, author, description, publisher, city, year, series, notes);
            Add(book);
            }   

                input.close();

        }

Answer 1

On this line:

if(!input.good())
    //return 1;
string callnumber;

You commented out the line with the semicolon and you're not using braces, and C++ is not white-space sensitive when it comes to spaces and newlines¹ between tokens, so by taking out the comment (and adding indentation) we can see that it's the equivalent of

if (!input.good())
    string callnumber;

And we can see that the declaration of callnumber is local to the if. Add braces or a semicolon to make the declaration of callnumber be outside the if (or just remove it completely):

if (!input.good()) { // or ;
    //return 1;
}
string callnumber;

---

¹ Except in macros

Answer 2

Because you've commented this line

if(!input.good())
    //return 1;

The string callnumber is only declared inside that scope and unusable outside of it.

Remove the if statement too or uncomment the return line