error in running the code

Create dependencies for bstep2d.cpp
/bin/sh: g++: not found
Compile bstep2d.cpp
g++ -DOLB_PRECOMPILED -O3 -Wall -I…/…/src -I…/…/src/external -I…/…/src/external/cvmlcpp -I…/…/src/external/boost -c bstep2d.cpp -o /home/nikul/OpenLBM/olb-0.6r0/examples/bstep2d/bstep2d.o
make: g++: Command not found
make: *** [/home/nikul/OpenLBM/olb-0.6r0/examples/bstep2d/bstep2d.o] Error 127

pls guide me on

The compilation process by default tries to use the GNU C++ compiler (g++) but it can’t find it on your system, probably because either it isn’t installed or it is in a non-standard location. If the latter, put that location in your $PATH (assuming you are using Linux). If its not there at all, you should install it, or if your system has a different C/C++ compiler, you can use that instead by specifying it in the Makefile (and adding its location to $PATH).