including a string as a parameter to a function in a header file? c++

Question

hello everyone, total newbie is here :) i have this header file, zeeheader.h, and i wrote some classes in it, i'm having problems giving a string as a parameter to one of the functions:

class DeliTest
{

public:

    void DeliCheck(Stack*,string);
    void ComCheck (unsigned,string);
    bool EofCheck (unsigned,string);
};

as i was implementinng it in the cpp file, i added #include to it, it seemed to be working, for example : as i was writing the "data." i got the "length()" appear by the intellisense, so i thought that it was working, but it wasn't. i got errors like:

syntax error : identifier 'string' overloaded member function not found in 'DeliTest'

this is one of the fucntions in the cpp file:

bool DeliTest::EofCheck(unsigned i, string data)
{

    if (i == data.length()-1)
        return 1;
    return 0;

}

am i supposed to be adding something to the header file??

Answer 1

You should #include <string> and keep in mind that string is part of the standard library so it is in the std namespace. You can either add: using namespace std; at the top of your header or fully qualify the string class with std::string where you use it. You really should get in the habit of using a fully qualified class name especially in a header file.

Answer 2

In the header file you need:

#include <string>

strings live in the std:; namespace, so your functions should look like:

void DeliCheck(Stack*, std::string);

and although it is not wrong to pass strings by value, as you are doing, it is more common and better practice to pass them by const reference:

void DeliCheck(Stack*, const std::string & );

Answer 3

I assume you are trying to use the standard string class? If so you need to add:

#include <string>

at the top of your header file. And then also prefix your usage of string with std::; e.g.

void DeliCheck(Stack*, std::string);

You may also want to name your arguments for clarity, and you probably don't want to pass the strings by value:

void DeliCheck(Stack* s, const std::string& name);

Answer 4

Make sure to #include <string>, and because strings are in the std namespace, you should declare your strings as std::string in the header.

As a sidenote, make sure you do NOT declare using namespace std; in your header files. This would cause any other headers or c/cpp files that include this header to also use the std namespace. This is called polluting the namespace.