BGI Error in opening C++ program with DOSBox -

i have program in c++ uses graphic.h want open dos-box when try error dos-box: bgi error: graphics not initialized (use 'initgraph')
have used initgraph in program in way:

gd=detect; initgraph(&gd,&gm,""); 

check initgraph(), should like

initgraph(&gd,&gm,"c:\tc\bgi"); 

if doesnot work try giving slash like:

initgraph(&gd,&gm,"c:\\tc\\bgi"); 

if again doesnot not work check environmental variables also.

you may refer existing post in bgi error, how resolve it?