“不可分类的声明”当引用函数时

Question

我正在学习函数中的虚拟参数和局部变量。

我正在使用的书中的练习之一是编写一个程序，询问用户的名字和姓氏，然后将这些名字连接在一起并打印全名。代码如下：

PROGRAM name_test
    IMPLICIT NONE

    ! Declare variables
    CHARACTER(LEN=12) :: first, last
    CHARACTER(LEN=30), EXTERNAL :: full_name

    ! 1. Ask for first name and family name, then read them
    PRINT *, "Please enter your first name"
    READ *, first
    PRINT *, "Please enter your family name"
    READ *, last

    ! 2. Join names together
    full_name(first, last)

    ! 3. Print welcome message
    PRINT *, "Welcome ", full_name(first, last)

END PROGRAM name_test

CHARACTER(LEN=*) FUNCTION full_name(first_name, last_name)
    IMPLICIT NONE

    ! Function which joins 2 names to form a full name

    ! Dummy argument declarations
    CHARACTER(LEN=*), INTENT(IN) :: first_name, last_name

    ! Local variables
    CHARACTER(LEN=LEN(first_name)) :: new_first_name
    CHARACTER(LEN=LEN(last_name)) :: new_last_name

    ! Use ADJUSTL to remove redundant leading blanks
    new_first_name = ADJUSTL(first_name)
    new_last_name = ADJUSTL(last_name)

    ! Join names
    full_name = TRIM(new_first_name)//" "//new_last_name

END FUNCTION full_name

当我尝试编译时，它出现一个错误，涉及第 15 行的函数调用：

full_name(first, last)

这是编译错误：

Error: Unclassifiable statement at (1)

Answer 1

您在 full_name(first,last) 行上遇到错误 - 尽管它给了我语法错误，但可能只是编译器不同。

您正在使用的函数返回一个值，因此您可以直接在 print 语句中使用它。在此之前不需要使用它，即使在此之前使用过它，您仍然需要将其值（它返回的值）分配给类似

string = full_name(first,last) 的

东西无论如何，我缩短了稍微高一点，就这样吧。

  program name_test
  implicit none

  character(len=12) :: first, last
  character(len=30), external :: full_name

  write(*,'("Please enter your first name : ",\)'); read(*,*)first
  write(*,'("Please enter your last name  : ",\)'); read(*,*)last
  write(*,'("Welcome ",A)')full_name(first,last)

  end program name_test


  function full_name(first,last)
  implicit none

  character(len=*) :: first, last
  character(len=30) :: full_name

  full_name = trim(adjustl(first))//" "//trim(adjustl(last))
  end function full_name