e的语法（自然日志） [英] syntax for e (natural logs)

问题描述

我想知道，如果有一个，那么常量e

的语法是什么。我认为它会在math.h中与''pi''一起出现，但它并不是b $ b似乎在那里，它确实存在吗？我在网上进行了很多搜索，但它很难搜索字母e，甚至尝试过自然日志，但是出现了

干。任何帮助将不胜感激，谢谢！


~Senturon

I was wondering what, if there is even one, the syntax for the constant e
is. I figured it would be in math.h right alongside ''pi'' but it doesn''t
seem to be there, does it in fact exist? i did many searches online but it
is hard to search for the letter ''e'', even tried natural logs but came up
dry. Any help would be appreciated, thank you!

~Senturon

推荐答案

Senturon写道：

Senturon writes:

我想知道，如果有一个，那么常量的语法是什么。我认为它会在math.h中与''pi'一起出现，但它似乎并不存在，它确实存在吗？我在网上进行了很多搜索，但很难找到字母e，甚至尝试过自然日志，但是却出现了干燥。任何帮助将不胜感激，谢谢！

I was wondering what, if there is even one, the syntax for the constant e
is. I figured it would be in math.h right alongside ''pi'' but it doesn''t
seem to be there, does it in fact exist? i did many searches online but it
is hard to search for the letter ''e'', even tried natural logs but came up
dry. Any help would be appreciated, thank you!

exp（1.0）

应该有效。它在< math.h>中。

exp(1.0)
should work. It''s in <math.h>.

Senturon写道：

Senturon wrote:

我想知道是什么，如果有的话甚至一个，常数的语法是。我认为它会在math.h中与''pi'一起出现，但它似乎并不存在，它确实存在吗？我在网上进行了很多搜索，但很难找到字母e，甚至尝试过自然日志，但是却出现了干燥。任何帮助将不胜感激，谢谢！

I was wondering what, if there is even one, the syntax for the constant e
is. I figured it would be in math.h right alongside ''pi'' but it doesn''t
seem to be there, does it in fact exist? i did many searches online but it
is hard to search for the letter ''e'', even tried natural logs but came up
dry. Any help would be appreciated, thank you!

事实上，C90

标准都不要求定义pi或e。始终定义的唯一宏math.h是HUGE_VAL。但是，

math.h确实提供了一些函数，你可以用它们在运行时获得这些

常量。


对于pi ：acos（-1.0）

对于e：exp（1.0）


或者，如果您宁愿在编译时使用它们，只需坚持下去在自己

常数：


的#define PI（3.1415926535897932384626433832795028841971693994L）

的#define E（2.7182818284590452353602874713526624977572470937L）


-

Derrick Coetzee

我将此新闻组发布到公共领域。我不承担所有

明示或暗示保证并承担所有责任。我不是专业人士。

In fact neither definitions of pi nor e are required by the C90
standard. The only macro math.h always defines is HUGE_VAL. However,
math.h does supply some functions which you can use to obtain these
constants at runtime.

For pi: acos(-1.0)
For e: exp(1.0)

Alternatively, if you''d rather have them at compile-time, just stick the
constants in yourself:

#define PI (3.1415926535897932384626433832795028841971693994L )
#define E (2.7182818284590452353602874713526624977572470937L )

--
Derrick Coetzee
I grant this newsgroup posting into the public domain. I disclaim all
express or implied warranty and all liability. I am not a professional.

Senturon写道：

Senturon wrote:

我想知道，如果有一个，那么常量e的语法是什么？ br />是。我认为它将在math.h中与''pi''


Pi不在< math.h>如果您的编译器处于符合标准的模式。但它似乎并不存在，它确实存在吗？我在网上进行了很多搜索，但很难找到字母e，甚至尝试过自然日志，但是却出现了干燥。任何帮助将不胜感激，谢谢！

I was wondering what, if there is even one, the syntax for the constant e
is. I figured it would be in math.h right alongside ''pi''
Pi isn''t in <math.h> if your compiler is in standard-conforming mode. but it doesn''t
seem to be there, does it in fact exist? i did many searches online but it
is hard to search for the letter ''e'', even tried natural logs but came up
dry. Any help would be appreciated, thank you!

输入您的代码：


const double pi = 3.14159265358979324;

const double e = 2.71828182845904524;


你当然可以反常使用

#define PI（4 * atan（1） ）

或

#define PI（6 * atan（1 / sqrt（3）））


以及

#define E（exp（1））

Put into your code:

const double pi=3.14159265358979324;
const double e= 2.71828182845904524;

you could, of course, perversely use
#define PI (4*atan(1))
or
#define PI (6*atan(1/sqrt(3)))

along with
#define E (exp(1))

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