C++ No viable conversion from string to const char *

Question

I'm using C++ (using CERN's ROOT framework) and I'm having a little problem with strings. I'm trying to label a histogram axis using a string defined by the user earlier in the code. Here are the relevant parts of the code:

string xlabel;

...
cout << "Enter x-axis label:" << endl;
getline(cin >> ws, xlabel);

...

hist->GetXaxis()->SetTitle(xlabel);

Where the last line is just syntax that ROOT uses (usually xlabel here would be in quotation marks and you can type in what you want the label to be, but I am trying to input the string defined earlier in the code.)

Anyway, when I compile this, I get the following error:

error: no viable conversion from 'string'
      (aka 'basic_string<char>') to 'const char *'
        hist->GetXaxis()->SetTitle(xlabel);
                                   ^~~~~~

I have tried re-defining xlabel as a const char * but it didn't like that either. Does anyone have any suggestions on how I could define this string?

Thanks in advance!

[std::string::c_str()](http://en.cppreference.com/w/cpp/string/basic_string/c_str). — πάντα ῥεῖ, Jun 12 '15 at 17:30

score 18 · Accepted Answer · answered Jun 12 '15 at 17:29

18

Do this:

hist->GetXaxis()->SetTitle(xlabel.c_str());
//                               ^^^^^^^^

answered Jun 12 '15 at 17:29

Kerrek SB

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It worked! I just looked up what c_str() does and it makes total sense now. Thank you so much! – khfrekek Jun 12 '15 at 17:33

C++ No viable conversion from string to const char *

1 Answers1