May I suggest codeproject.com for some plotting programs. You can check for example: http://www.codeproject.com/Articles/1546/Plot-Graphic-Library .

I would suggest gnuplot. Btw, did you mean 'takes a data file and produces ...'?

There are many, many applications specialized at visualization of data. However, if program development goes parallel with generation and inspection of data it is often advantageous to have the visualization tools directly available as C++ classes. Then adding a few lines of debug code lets data be generated under visual control that otherwise would be generated 'in the dark'. This is the way I work since more than 20 years and which led to the C++ class system which I call C+- (since it makes active use only of a subset of the rather complex C++ syntax). C+- can freely be downloaded from my website, together with examples and documentation. Feel free to ask for help if you consider using this tool.

http://www.ulrichmutze.de

Surely you're joking Mr. Nyayn. Your code example deals with graphs in the sense of mathematical graph theory, not with data plotting.

I agree with Ulrich Mutze, gnuplot is a plausible option.

I've adapted a class that provides data plotting using gnuplot and the fast light toolkit (FLTK) :

http://code.google.com/p/pyran/source/browse/CPP-libs/myFl/Fl_Gnuplot.hpp

http://code.google.com/p/pyran/source/browse/CPP-libs/myFl/Fl_Gnuplot.cpp

Maybe it helps ...

To my answer above I may add an example implementation, which can be found there

http://code.google.com/p/pyran/source/browse/CPP-libs/myFl/examples/demo_FFT.cpp.

A screenshot is also attached for those who are not familiar with fltk :)

Gnuplot is OK, but lately I have been really liking the plotting capabilities of R. The plots look very nice and it is easy to export them as PDFs which can be used in TeX.

Try it

http://www.codeproject.com/Articles/421275/2D-Drawing-Doc-View-architecture

No doubt: gnuplot