Unable to use a string as a parameter on an another class

Question

I created a simple function in my cpp that prints out a text. Here's the code:

#include "Sally.h"
#include <iostream>
using namespace std;

Sally::Sally()
{

}

void Sally::tell(string t){

    cout << t << endl;

}

and here's how I prototype it on my .h file:

#ifndef SALLY_H
#define SALLY_H
class Sally
{
    public:

        Sally();
        void tell(string t);
    protected:

    private:
};

#endif // SALLY_H

Here are the errors:

Sally.h|8|error: 'string' has not been declared|
Sally::tell(std::__cxx11::string)' does not match any in class 'Sally'|
Sally.h|8|error: candidate is: void Sally::tell(int)|

It gives me an error whenever I build it. It doesn't have any problems at all if I'm using int as a parameter. So the problem is that I wish to use a string as a parameter.

Don't post the error etc. in comments, [edit] your question to put it in it. — Angew is no longer proud of SO, May 11 '18 at 07:48
I've edited the post. Im sorry didnt know that it contains both cpp. It now has the .h file — Jordan Mari Celestino, May 11 '18 at 07:51
now you just need to show us the compilation error. As you can see [this](https://wandbox.org/permlink/JCEYfUvEiErCFsMm) code has no issues? So apart from yours being across multiple files, what is different? — Paul Rooney, May 11 '18 at 07:52
You are probably only `using namespace std` in one of your files, but writing `string` in both. Best practice is to never use `using namespace std` and just type out `std::string`, but you can also include `using namespace std` in both files. — super, May 11 '18 at 08:02
in the header use the full name `std::string`. Don't get in the habit of `using namespace std;` in header files. — Paul Rooney, May 11 '18 at 08:04
That fixed it. Thank you guys for helping me. I'm new to c++. I'm so sorry. Haha — Jordan Mari Celestino, May 11 '18 at 08:05
That's what I would recommend. `using namespace std;` pulls all symbols of `namespace std` into global namespace. This might produce surprising effects (and hard-to-track errors) as it might change where which symbol is found and which other symbols are eclipsed by this. Have a look at this Q/A to learn more: [SO: Why is “using namespace std” considered bad practice?](https://stackoverflow.com/q/1452721/7478597). — Scheff's Cat, May 11 '18 at 08:23

score 1 · Answer 1 · answered May 11 '18 at 11:44

1

do some changes to your .h file:

#include <string>

and add std:: in front of your string:

void tell(std::string t);

answered May 11 '18 at 11:44

skeller

1,151
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Unable to use a string as a parameter on an another class

1 Answers1