角色（ Characters）

Fortran语言可以将字符视为单个字符或连续字符串。

字符可以是从基本字符集中取出的任何符号，即字母，十进制数字，下划线和21个特殊字符。

字符常量是固定值字符串。

内在数据类型character存储字符和字符串。 字符串的长度可以由len说明符指定。 如果未指定长度，则为1.您可以按位置引用字符串中的单个字符; 最左边的字符位于第1位。

品格宣言

声明字符类型数据与其他变量相同 -

type-specifier :: variable_name

例如，

character :: reply, sex

你可以分配一个值，如，

reply = ‘N’ 
sex = ‘F’

以下示例演示了字符数据类型的声明和使用 -

program hello
implicit none
   character(len = 15) :: surname, firstname 
   character(len = 6) :: title 
   character(len = 25)::greetings
   title = 'Mr. ' 
   firstname = 'Rowan ' 
   surname = 'Atkinson'
   greetings = 'A big hello from Mr. Bean'
   print *, 'Here is ', title, firstname, surname
   print *, greetings
end program hello

编译并执行上述程序时，会产生以下结果 -

Here is Mr. Rowan Atkinson       
A big hello from Mr. Bean

字符串联

连接运算符//连接字符。

以下示例演示了这一点 -

program hello
implicit none
   character(len = 15) :: surname, firstname 
   character(len = 6) :: title 
   character(len = 40):: name
   character(len = 25)::greetings
   title = 'Mr. ' 
   firstname = 'Rowan ' 
   surname = 'Atkinson'
   name = title//firstname//surname
   greetings = 'A big hello from Mr. Bean'
   print *, 'Here is ', name
   print *, greetings
end program hello

编译并执行上述程序时，会产生以下结果 -

Here is Mr.Rowan Atkinson       
A big hello from Mr.Bean

Some 字符函数

下表显示了一些常用的字符函数以及描述 -

例子1 (Example 1)

此示例显示了index函数的使用 -

program testingChars
implicit none
   character (80) :: text 
   integer :: i 
   text = 'The intrinsic data type character stores characters and   strings.'
   i=index(text,'character') 
   if (i /= 0) then
      print *, ' The word character found at position ',i 
      print *, ' in text: ', text 
   end if
end program testingChars

编译并执行上述程序时，会产生以下结果 -

The word character found at position 25
in text : The intrinsic data type character stores characters and strings.  

例子2 (Example 2)

此示例演示了trim功能的使用 -

program hello
implicit none
   character(len = 15) :: surname, firstname 
   character(len = 6) :: title 
   character(len = 25)::greetings
   title = 'Mr.' 
   firstname = 'Rowan' 
   surname = 'Atkinson'
   print *, 'Here is', title, firstname, surname
   print *, 'Here is', trim(title),' ',trim(firstname),' ', trim(surname)
end program hello

编译并执行上述程序时，会产生以下结果 -

 Here isMr.   Rowan          Atkinson       
 Here isMr. Rowan Atkinson

例子3 (Example 3)

这个例子演示了achar功能的使用 -

program testingChars
implicit none
   character:: ch
   integer:: i
   do i = 65, 90
      ch = achar(i)
      print*, i, ' ', ch
   end do
end program testingChars

编译并执行上述程序时，会产生以下结果 -

65  A
66  B
67  C
68  D
69  E
70  F
71  G
72  H
73  I
74  J
75  K
76  L
77  M
78  N
79  O
80  P
81  Q
82  R
83  S
84  T
85  U
86  V
87  W
88  X
89  Y
90  Z

检查字符的词法顺序

以下函数确定字符的词汇顺序 -

Example 4

以下功能演示了使用方法 -

program testingChars
implicit none
   character:: a, b, c
   a = 'A'
   b = 'a'
   c = 'B'
   if(lgt(a,b)) then
      print *, 'A is lexically greater than a'
   else
      print *, 'a is lexically greater than A'
   end if
   if(lgt(a,c)) then
      print *, 'A is lexically greater than B'
   else
      print *, 'B is lexically greater than A'
   end if  
   if(llt(a,b)) then
      print *, 'A is lexically less than a'
   end if
   if(llt(a,c)) then
      print *, 'A is lexically less than B'
   end if
end program testingChars

编译并执行上述程序时，会产生以下结果 -

a is lexically greater than A
B is lexically greater than A
A is lexically less than a
A is lexically less than B