program gauss_main2

       integer n, np, m, mp, i
       parameter (np=10, mp=20)       
       real a(np,np), b(np,mp)
       character*40 filename1, filename2

       write (*,*)'Please tell me the dimension n of the matrix A(n,n):'
       read (*,*) n
       if (n.gt.np) stop 'n can not be larger than np'
       write (*,*) 'Please give the size m of the augmented b(n,m):'
       read (*,*) m
       if (m.gt.mp) stop 'm can not be larger than mp'

       write (*,*) 'Please give the file name that contains A :'
       read (*,*) filename1
       write (*,*) 'Please give the file name that contains b :'
       read (*,*) filename2

       open (unit=20, file=filename1)
       do i=1,n
         read (20,*) ( a(i,j), j=1,n )
       enddo
       close(20)

       open (unit=20, file=filename2)
       do i=1,n
         read (20,*) ( b(i,j), j=1,m )
       enddo
       close(20)
       
       call gaussj(a,n,np,b,m,mp)
      
       write(*,*) 'The inverse matrix is :' 
       do i=1,n
         write (*,*) ( a(i,j), j=1,n )
       enddo
       write (*,*)
       write (*,*) 'and the solution matrix is :'
       do i=1,n
         write (*,*) ( b(i,j), j=1,m )
       enddo

       end