C This subroutine prints out the global array

      SUBROUTINE PRNT
      IMPLICIT NONE
      REAL A(5,5)
      COMMON /MATRIX/ A
      INTEGER I, J

      DO I = 1, 5
         WRITE (UNIT=*, FMT=20) (A(I,J), J=1,5)
      ENDDO

 20   FORMAT (5F5.2)
      END
            

C This subroutine computes the square root of every element in
C the global array.

      SUBROUTINE ROOT
      IMPLICIT NONE
      REAL A(5,5)
      COMMON /MATRIX/ A
      INTEGER I, J

      DO I = 1, 5
         DO J = 1, 5
            A(I,J) = SQRT(A(I,J))
         ENDDO
      ENDDO

      CALL PRNT
      END


C The main program initializes the global array

      PROGRAM COMM
      IMPLICIT NONE
      REAL A(5,5)
      COMMON /MATRIX/ A
      INTEGER I, J

      DO I = 1, 5
         DO J = 1, 5
            A(I,J) = I*(J+2.0)
         ENDDO
      ENDDO

      CALL ROOT
      STOP
      END