Fortran95/2003 Explained 12-4

allocatable components. TYPE 構造体の中に、allocatable 属性の変数を入れられるようになりました。Pointer の場合とはメモリー上での連続性や、コピーの時の振る舞いが違うようです。

実行結果

ソースコード

MODULE real_polunomial_module
IMPLICIT NONE
 TYPE real_polynomial
   REAL, ALLOCATABLE :: coeff(:)
 END TYPE real_polynomial
 INTERFACE OPERATOR(+)
   MODULE PROCEDURE rp_add_rp
 END INTERFACE OPERATOR(+)
CONTAINS
!---------------------------------------
TYPE(real_polynomial) FUNCTION rp_add_rp(p1, p2)
 TYPE(real_polynomial), INTENT(IN) :: p1, p2
 INTEGER :: m, m1, m2
 m1 = UBOUND(p1%coeff, 1)
 m2 = UBOUND(p2%coeff, 1)
 ALLOCATE( rp_add_rp%coeff( MAX(m1, m2) ) )
 m = MIN(m1, m2)
 rp_add_rp%coeff(:m) = p1%coeff(:m) + p2%coeff(:m)  
 IF (m1 > m) rp_add_rp%coeff(m + 1:) = p1%coeff(m + 1:)
 IF (m2 > m) rp_add_rp%coeff(m + 1:) = p1%coeff(m + 1:)
 RETURN
END FUNCTION rp_add_rp
!---------------------------------------
END MODULE real_polunomial_module
!=========================================
PROGRAM example
USE real_polunomial_module
IMPLICIT NONE
 TYPE (real_polynomial) :: p, q, r
 p = real_polynomial( [4.0, 2.0, 1.0] ) ! 4 + 2x + x**2
 q = real_polynomial( [-1.0, 1.0] )
 r = p + q
 PRINT *, 'Coefficients are: ', r%coeff
STOP   
END PROGRAM example