fatal error: armadillo linux installation

C++ library for linear algebra & scientific computing

user@hostname:~$ cd Desktop/
user@hostname:~/Desktop$ g++ arm.cpp -l armadillo
qb.cpp: In function ‘int main()’:
qb.cpp:180:31: error: ‘expmat’ was not declared in this scope
   cx_mat RowT= expmat(-II*Hc*t)*Row*expmat(II*Hc*t); //evolved state
                              

ccc@ccc:~$ g++ qb.cpp -l armadillo
qb.cpp:3:20: fatal error: armadillo: No such file or directory
compilation terminated.
ccc@ccc:~$ g++ qb.cpp -larmadillo
qb.cpp:3:20: fatal error: armadillo: No such file or directory
compilation terminated.

Solution :- 
Download armadillo from http://arma.sourceforge.net/download.html

#wget http://sourceforge.net/projects/arma/files/armadillo-9.200.7.tar.xz 

I am using "wget" 
Linux Shell / terminal based downloading tool program.

#tar -xvf armadillo-9.200.7.tar.xz 
#cd armadillo-9.200.7
#./configure
#make 
#make install 

DONE..