! matrix product
PROGRAM ex6_6

  IMPLICIT NONE
  INTEGER, DIMENSION(:,:), ALLOCATABLE :: a, b, c
  INTEGER :: m = 0, n = 0, k = 0, i, j, h

  DO WHILE( m <= 0 .OR. n <= 0 .OR. k <= 0 )
    PRINT '(1X, A)', 'Input array size m, n, k ( > 0 ) : '
    READ *, m, n, k
  END DO
  ALLOCATE( a(m,n), b(n,k), c(m,k) )

  PRINT '(1X,A)', 'Input elements of a in a matrix form: '
  READ *, ( ( a(i,j), j = 1, n ), i = 1, m )
  PRINT '(1X, A)', 'Input elements of b in a matrix form: '
  READ *, ( ( b(i,j), j = 1, k ), i = 1, n )

  DO i = 1, m
    DO j = 1, k
      c(i,j) = 0
      DO h = 1, n
        c(i,j) = c(i,j) + a(i,h) * b(h,j)
      END DO
    END DO
  END DO

  DO i = 1, m
    PRINT '(10I5)', ( c(i,j), j = 1, k )
  END DO

END PROGRAM ex6_6