! 例題 9-3  スカラ積とベクトル積 ［構造型変数名での出力 ］
PROGRAM ex9_3

  IMPLICIT NONE
  REAL :: s
  TYPE vector
    REAL :: x, y, z
  END TYPE vector
  TYPE ( vector ) :: a, b, c

  PRINT *, 'Input 3 components of the first vector: '
  READ *, a
  PRINT *, 'Input 3 components of the second vector: '
  READ *, b

  ! s = a * b とは書けない
  s = a%x * b%x + a%y * b%y + a%z * b%z
  PRINT '( 1P, "a.b = ", E9.2 )', s
  c = vector_product( a, b )
  PRINT '( 1P, "a^b = (", E9.2, ",", E9.2, ",", E9.2, ")" )', c

CONTAINS

  FUNCTION vector_product( u, v ) RESULT ( w )

    IMPLICIT NONE
    TYPE ( vector ) :: u, v, w

    w%x = u%y * v%z - u%z * v%y
    w%y = u%z * v%x - u%x * v%z
    w%z = u%x * v%y - u%y * v%x

  END FUNCTION vector_product

END PROGRAM ex9_3