_C_o_n_c_a_t_e_n_a_t_e _a_n_d _P_r_i_n_t
	
	     cat(... , sep="")
	
	_V_a_l_u_e:
	
	     cat converts its arguments to character strings, con-
	     catenates them, separating them by the given sep=
	     string, and then prints them.
	
	     cat is useful for producing output in user defined
	     functions.
	
	_E_x_a_m_p_l_e_s:
	
	     # print an informative message
	     cat("iteration = ",iter,"\n")