RosettaCodeData/Task/Identity-matrix/Eiffel/identity-matrix.e

class
   APPLICATION

inherit
   ARGUMENTS

create
   make

feature {NONE} -- Initialization

   make
         -- Run application.
      local
          dim : INTEGER -- Dimension of the identity matrix
      do
          from dim := 1 until dim > 10 loop
            print_matrix( identity_matrix(dim) )
            dim := dim + 1
            io.new_line
         end

      end

feature -- Access

   identity_matrix(dim : INTEGER) : ARRAY2[REAL_64]

      require
         dim > 0
      local
         matrix : ARRAY2[REAL_64]
         i : INTEGER
      do

         create matrix.make_filled (0.0, dim, dim)
         from i := 1 until i > dim loop
            matrix.put(1.0, i, i)
            i := i + 1
         end

         Result := matrix
      end

   print_matrix(matrix : ARRAY2[REAL_64])
      local
         i, j : INTEGER
      do
         from i := 1 until i > matrix.height loop
            print("[ ")
            from j := 1 until j > matrix.width loop
               print(matrix.item (i, j))
               print(" ")
               j := j + 1
            end
            print("]%N")
            i := i + 1
         end
      end

end