gcc -o demo demo.c
or run via EiC:
eic demo.c
The basic method for EiC's gnuplot API works like this:
#include "gnuplot/gplot.h"
...
plot_t *p = openPlot("name of plot");
int a = 1;
send2plot(p,"plot [x=%d:%d] cos(x)",-a,a);
int i; float A[100];
for(i=0;i<100;++i) A[i] = i/3.0;
plotData(A,100,p,plotFloats);
closePlot(p);