Error with string as a constructor parameter?

[Robotics Guy]

Here's my code:

#include <string>

#ifndef MAIN_H

class MyClass
{
public:
	MyClass();
	MyClass(string myString);
};

MyClass::MyClass()
{
}

MyClass::MyClass(string myString)
{
}

#endif

Visual Studio gives me the following error:



If I change myString to type INT, there is no compilation error. So what am I doing wrong?

[GCDEF]

What is planetName? Show all your relevant code.

[Robotics Guy]

Sorry, I removed irrelevant portions of code to simplify the problem. planetName = myString.

[jnmacd]

I can't see the link, but your compiler does not know what 'string' is.

#include <string>

#ifndef MAIN_H

class MyClass
{
public:
	MyClass();
	MyClass(std::string myString);
};

MyClass::MyClass()
{
}

MyClass::MyClass(std::string myString)
{
}

#endif

[Lindley]

Since that's in a header, you should be fully-qualifying std::string.

[Robotics Guy]

Oh, thanks! I didn't realize I had the "using namespace std;" line below the inclusion of this header file and I had no idea what this error meant..

Appreciate your help!

[Lindley]

Oh, thanks! I didn't realize I had the "using namespace std;" line below the inclusion of this header file and I had no idea what this error meant..

Appreciate your help!

By and large, it's best not to rely on "using" statements in header files for two reasons:

1) You don't want the inclusion of a header file to automatically bring a given namespace into scope, because that could preclude using two particular headers together for no good reason in some cases.

2) You don't want the header to compile or break based on the order of inclusion.

That said, "using" statements are permissible in header files so long as they have restricted scope (such as an inline function implementation).