Re: plotting data c++

ok guys here is the problem again, i am plotting x,y data, floats to be 
precise, must be in C, C++, the hardway, no perl or python just know how 
to us perl a little, the idea is to have the application data to do the 
approximation of a square wave by means of fourier series, the job is 
done, now the problem is the gui, well i tried tk with perl and 
everything went smootly, till the part of converting perl to C, and 
including the interpreter and all that stuff, truly i did not get it 
right so it freezes and is buggy, so well back in track i found my self 
on the same road, just C, the gui I plan to do them with windowsapi they 
are the lesser problem, mingw, but the plotting data per se is the
biggest problem, i tried reading the wiki for libgd, and let me tell you 
it is not for noobs, or at least not for the dumbest as me.

The algorithm says more or less:
number or harmonics, number of data points, using gui, some routines, 
and then we have and arbitrary number of data with a max value of 1 and 
the minimum of 0, arranged in pairs of x,y,

i have the suspicion it is straightforward, but i seem to fail, i am 
still googling, found koolplot, which i think uses libgd, did not work 
for my mingw, so, any directions where to look...