后缀增量 [英] Postfix increment
问题描述
您好！
我发现有一个有趣的事情是使用后缀运算符++。
什么应该包含变量i以下代码：
int i = 5;
i = i ++;
在VC ++ 7.1和VC ++ 2005 beta中2变量i包含6.
但在C＃7.1和C＃2005 beta 2中变量i包含5.
行为是否正确？谁能解释一下结果是什么呢？
祝你好运，
Oleg。
你好
嗯，看起来很奇怪。我已经在C ++和C＃（VS 2003）上进行了测试，并且
得到了不同的结果。
我期待在C＃中得到6，但是给了我5！
所以，看起来我们有下一个算法：
t = i; //一些临时变量或寄存器
i ++; //这里我们得到i = 6;
i = t; //这里我们回来了i = 5
很奇怪!!!
-
最好的问候，
Andrew
http://www.codeproject.com/script/pr...asp?id=1181072
" Oleg Kharitonov" < KH ***** @ mail.ru>在消息中写道
news：OR ************* @ tk2msftngp13.phx.gbl ...你好！
我用postfix operator ++找到了一个有趣的东西。
在得到以下代码之后应该包含变量i：
int i = 5; <在VC ++ 7.1和VC ++ 2005 beta 2中，变量i包含6.
但在C＃7.1和C＃2005 beta 2中，变量i包含5个。
i = i ++;
/>
行为是否正确？谁能解释一下这是什么结果呢？
最好的问候，
Oleg。
有趣的评论：）
但我对你的评论有疑问...... VC ++有托管或非托管
代码？我可以推测未受管理的情况......
" Oleg Kharitonov" < KH ***** @ mail.ru> schrieb im Newsbeitrag
新闻：或者************* @ tk2msftngp13.phx.gbl ...你好！
我用postfix operator ++找到了一个有趣的东西。
在得到以下代码之后应该包含变量i：
int i = 5; <在VC ++ 7.1和VC ++ 2005 beta 2中，变量i包含6.
但在C＃7.1和C＃2005 beta 2中，变量i包含5个。
i = i ++;
/>
行为是否正确？谁能解释什么是正确的结果？
最好的问候，
Oleg。
C＃的行为是正确的，C ++的行为是不正确。
来自C ++参考：
重要的是要注意后缀增量或减量表达式
计算前面的表达式的值应用
各自的运营商。
来自C＃的关于后缀增量的参考：
操作的结果是值之前的操作数是
递增。
因此示例中i ++的返回值是5而不是6.
Hello!
I have found an interesting thing with postfix operator ++.
What should contain the variable i after exceution the following code:
int i = 5;
i = i++;
In VC++ 7.1 and VC++ 2005 beta 2 the variable i contains 6.
But in C# 7.1 and C# 2005 beta 2 the variable i contains 5.
Is it behaviour correct? Can anyone explain what is the correct result?
Best regards,
Oleg.
Hello
Hmmm, it looks really strange. I''ve tested it on C++ and C# (VS 2003) and
got different result.
I was expecting to get 6 in C#, but gave me 5 !
So, it looks like it we have the next algorithm:
t = i; // some temp variable or register
i++; // here we get i=6;
i=t; // here we get back i=5
Very strange !!!
--
With best regards,
Andrew
http://www.codeproject.com/script/pr...asp?id=1181072
"Oleg Kharitonov" <kh*****@mail.ru> wrote in message
news:OR*************@tk2msftngp13.phx.gbl...Hello!
I have found an interesting thing with postfix operator ++.
What should contain the variable i after exceution the following code:
int i = 5;
i = i++;
In VC++ 7.1 and VC++ 2005 beta 2 the variable i contains 6.
But in C# 7.1 and C# 2005 beta 2 the variable i contains 5.
Is it behaviour correct? Can anyone explain what is the correct result?
Best regards,
Oleg.
Interesting remark :)
But I have a question on your remark ... VC++ with managed or unmanaged
code ? I can speculate on the unmanaged situation ...
"Oleg Kharitonov" <kh*****@mail.ru> schrieb im Newsbeitrag
news:OR*************@tk2msftngp13.phx.gbl...Hello!
I have found an interesting thing with postfix operator ++.
What should contain the variable i after exceution the following code:
int i = 5;
i = i++;
In VC++ 7.1 and VC++ 2005 beta 2 the variable i contains 6.
But in C# 7.1 and C# 2005 beta 2 the variable i contains 5.
Is it behaviour correct? Can anyone explain what is the correct result?
Best regards,
Oleg.
The behavior of C# is correct, the behavior of C++ is incorrect.
From C++ reference:
It is important to note that a postfix increment or decrement expression
evaluates to the value of the expression prior to application of the
respective operator.
From C# reference about postfix increment:
The result of the operation is the value of the operand before it has been
incremented.
So the return value of i++ in the example is 5 not 6.
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