Fortran-relational-operators

Fortran-関係演算子

次の表は、Fortranでサポートされているすべての関係演算子を示しています。 変数 A が10を保持し、変数 B が20を保持すると仮定します-

Operator	Equivalent	Description	Example
==	.eq.	Checks if the values of two operands are equal or not, if yes then condition becomes true.	(A == B) is not true.
/=	.ne.	Checks if the values of two operands are equal or not, if values are not equal then condition becomes true.	(A != B) is true.
>	.gt.	Checks if the value of left operand is greater than the value of right operand, if yes then condition becomes true.	(A > B) is not true.
<	.lt.	Checks if the value of left operand is less than the value of right operand, if yes then condition becomes true.	(A < B) is true.
>=	.ge.	Checks if the value of left operand is greater than or equal to the value of right operand, if yes then condition becomes true.	(A >= B) is not true.
⇐	.le.	Checks if the value of left operand is less than or equal to the value of right operand, if yes then condition becomes true.	(A ⇐ B) is true.

例

Fortranで利用可能なすべての論理演算子を理解するために、次の例を試してください-

! this program checks relational operators
implicit none

   ! variable declaration
   integer :: a, b

   ! assigning values
   a = 10
   b = 20

   if (a .eq. b) then
      print *, "Line 1 - a is equal to b"
   else
      print *, "Line 1 - a is not equal to b"
   end if

   if (a > b) then
      print *, "Line 2 - a is greater than b"
   else
      print *, "Line 2 - a is less than b"
   end if

   if (a <= b) then
      print *, "Line 3 - a is less than or equal to b"
   else
      print *, "Line 3 - a is greater than b"
   end if

   a = 20
   b = 20

   if (a .eq. b) then
      print *, "Line 4 - a is equal to b"
   else
      print *, "Line 4 - a is not equal to b"
   end if
end

上記のプログラムをコンパイルして実行すると、次の結果が生成されます-

Line 1 - a is not equal to b
Line 2 - a is less than b
Line 3 - a is less than or equal to b
Line 4 - a is equal to b