As WD said, you're probably missing the .BGI file in the same folder as your executable, just out of curiosty add
1cleardevice;
after initgraph and before closegraph
and
1writeln(graphresult);
after closegraph and before end. so you can see what (if anything) went wrong as a numerical result since, at the moment, it's doing nothing and it might indeed be working and you're just simply not noticing (on exit TP restores the CRT mode and it exits right after closegraph; if you want it to wait, add
1readln;
after cleardevice, so you can see your wonderful black graphics screen).