How to retrieve the specific element from an array of std::strings as a LPCSTR?

In C++, I've got a string array variable called:

...
/* set the variable */
string fileRows[500];
...
/* fill the array with a file rows */
while ( getline(infile,sIn ) )
{
    fileRows[i] = sIn;
    i++;
}

and an object which has this:

string Data::fileName(){
    return (fileRows);
}

I would like to make a function which return an array, and after that i would like to call it something like this:

Data name(hwnd);
MessageBox(hwnd, name.fileName(), "About", MB_OK);

But i get this error:

cannot convert 'std::string* {aka std::basic_string}' to 'LPCSTR {aka const char}' for argument '2' to 'int MessageBoxA(HWND, LPCSTR, LPCSTR, UINT)'

If i would like to show the 5. element of the array, how to convert it?

fileRows is an array of 500 elements. If you want to return the array so that you can later access the n-th element, you should return the pointer to the beginning of the array. For example:

string* Data::fileName(){
        return fileRows;
}

Although it is probably better to use:

const string& Data::getFileName(size_t index){
        return fileRows[index];
}

Using the first method, you can access the n-th element using:

data.filename()[n];

So, if you want to access the 5th element of the array you should use:

data.filename()[4];

On the other hand, the function MessageBox needs a const char *. So you must call the c_str() method to get the pointer:

Data name(hwnd);
MessageBox(hwnd, name.fileName()[4].c_str(), "About", MB_OK);