anchor.diff:  
           write (*,*) " done!"
   
  +        111 format (A25, I20, A, F0.3, A)
  +        222 format (A25, I5, I5, I5, I5, A, F0.3, A)
   
         end program benchmark
   
  
positive.code: 
          use fibonacci
          use perfect_number
          use color_map
          use mandelbrot
  
          implicit none
  
negative.code:         call system_clock(tic)
          call perfect_numbers(10000, res_pn)
          call system_clock(toc)
          write (*,222) "perfect_numbers(10000) = ", res_pn, &
            & " Elapsed time: ", float(toc-tic)/rate * 1000, "ms"
  
          write (*,*) ""
  