VF中用数学函数，需要包含那些库

digital

VFortran中，判断符合的Sgn为何不能用啊。

如Sgn(-5)应该为－1的，但编译错误，
LNK2001: unresolved external symbol _SGN@4

SCIE

没有Sgn这个函数，要用SIGN函数
SIGN
Elemental Intrinsic Function (Generic): Returns the absolute value of the first argument times the sign of the second argument.

Syntax

result = SIGN (a, b)

a
(Input) Must be of type integer or real.

b
Must have the same type and kind parameters as a.

c = SIGN (5.2, -3.1)   ! returns -5.2
c = SIGN (-5.2, -3.1)  ! returns -5.2
c = SIGN (-5.2, 3.1)   ! returns  5.2

因此你的求符号的应该是：

SIGN(1, -5) 得到 -1

digital

我从COMPAQ VISUAL FORTRAN带的帮助里看到是这样一个结果。

请问大侠你是从那里查到的。谢谢！

Microsoft® Visual Basic® Scripting Edition
Sgn Function   Language Reference
Version 1


See Also

--------------------------------------------------------------------------------

Description
Returns an integer indicating the sign of a number.
Syntax
Sgn(number)
The number argument can be any valid numeric expression.

Return Values
The Sgn function has the following return values:
If number is Sgn returns
Greater than zero  1
Equal to zero  0
Less than zero -1

Remarks
The sign of the number argument determines the return value of the Sgn function.
The following example uses the Sgn function to determine the sign of a number:

Dim MyVar1, MyVar2, MyVar3, MySign
MyVar1 = 12: MyVar2 = -2.4: MyVar3 = 0
MySign = Sgn(MyVar1)    ' Returns 1.
MySign = Sgn(MyVar2)    ' Returns -1.
MySign = Sgn(MyVar3)    ' Returns 0.

digital

谢谢，我也从帮助里查到了sign
谢谢了

SCIE

digital wrote:
我从COMPAQ VISUAL FORTRAN带的帮助里看到是这样一个结果。

请问大侠你是从那里查到的。谢谢！

Microsoft® Visual Basic® Scripting Edition
Sgn Function   Language Reference
Version 1
...

This help information is about Visual Basic Scripting. It's not the help for Visual Fortran.

lijingwei_

帮助文件里面的文字有不同颜色，好像只有绿色还是黑色才是FORTRAN的，其它都是别的语言的函数，真是弄不明白，为什么要把它们放在FORTRAN语言的帮助里面。