true/TRUE和null/NULL之间的差异 [英] Differences between true/TRUE and null/NULL

问题描述

你好.

我有一个小问题，似乎无法找到一个好的答案.

true/false和TRUE/FALSE之间的区别是什么(小写字母与大写字母).在大多数情况下，似乎并没有真正的区别，但在某些情况下确实会收到警告.

还有... null 和NULL有什么区别?

我能弄清楚的是，这与从C到C ++的开发有关吗?

感觉像一个愚蠢的问题...但是我真的没有头绪. :cool:

Hello out there.

I have a small question that I seem unable to find a good answer at.

What is the differences between true/false and TRUE/FALSE (small vs cap. letters). In most cases it seems there are no real differences but I do get warnings in some cases.

Also... what is the difference between null and NULL?

All I can figure out is that this has something with the developmen from C to C++?

Feels like a stupid question... but I don''t really have a clue. :cool:

推荐答案

true和false只是bool类型的有效值
bool mybool = true;

TRUE是#d​​efine TRUE 1，即整数值1
FALSE是#define FALSE 0，即整数值0
适用于BOOL

#define BOOL int
BOOL myBOOL = TRUE;
这也是可能的
myBOOL = 6;
这就是为什么引入bool


nullptr指向没有地址/值的指针(我认为是c#，它为null)

NULL是#define NULL 0，但出于传统原因在其中用作nullptr


TRUE，FALSE和NULL是#出于传统原因在其中定义

true，false，nullptr是该语言的一部分，并被编译器识别

true and false are only valid values for type bool
bool mybool = true;

TRUE is #define TRUE 1 i.e. integer value 1
FALSE is #define FALSE 0 i.e. integer value 0
applied to BOOL

#define BOOL int
BOOL myBOOL = TRUE;
This is also possible
myBOOL = 6;
which is why bool was introduced


nullptr refers to a pointer with no address/value (null I think is c#)

NULL is #define NULL 0 but used as nullptr there for legacy reasons


TRUE, FALSE, NULL are #defines there for legacy reasons

true, false, nullptr are part of the language and recognised by the compiler

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