在C＃中解释后递增 [英] Explaining post-increment in C#

问题描述

可能重复：结果
的行为，并在C＃中的评价订单

我有一些代码

static void Main(string[] args)
{
    int j = 0;
    for (int i = 0; i < 10; i++) 
        j = j++;
    Console.WriteLine(j);
}

为什么答案是0？

Why answer is 0 ?

推荐答案

这是因为路的 ++递增工作。 操作的顺序MSDN文章中解释这可以在这里看到（有人请纠正我，如果我读这一个错误的规范：））：

This is because of the way the ++ increment works. The order of operations is explained in this MSDN article This can be seen here (somebody please correct me if I am reading the spec on this one wrong :)):

int j = 2;
//Since these are value objects, these are two totally different objects now
int intermediateValue = j;
j = 2 + 1
//j is 3 at this point
j = intermediateValue;
//However j = 2 in the end

既然是一个值对象时，两个物体在这一点上（Ĵ和 intermediateValue ）是不同的。旧的结果表明：J递增，而是因为你使用了​​相同的变量名，它是输给你。我建议在值对象的差异读了对参考对象，也。

Since it is a value object, the two objects (j and intermediateValue) at that point are different. The old j was incremented, but because you used the same variable name, it is lost to you. I would suggest reading up on the difference of value objects versus reference objects, also.

如果您曾经为变量使用单独的名称，那么你就能够看到这个故障好。

If you had used a separate name for the variable, then you would be able to see this breakdown better.

int j = 0;
int y = j++;
Console.WriteLine(j);
Console.WriteLine(y);
//Output is 
// 1
// 0

如果这是一个类似的运营商一个参照对象，如预期那么这将最有可能的工作。特别指出的是如何只创建一个新的指向相同的参考。

If this were a reference object with a similar operator, then this would most likely work as expected. Especially pointing out how only a new pointer to the same reference is created.

public class ReferenceTest
{
    public int j;
}

ReferenceTest test = new ReferenceTest();
test.j = 0;
ReferenceTest test2 = test;
//test2 and test both point to the same memory location
//thus everything within them is really one and the same
test2.j++;
Console.WriteLine(test.j);
//Output: 1

回到原点，虽然：）

Back to the original point, though :)

如果你做到以下几点，那么你会得到预期的结果。

If you do the following, then you will get the expected result.

j = ++j;

这是因为增量首先出现，然后是分配。

This is because the increment occurs first, then the assignment.

然而，++可以单独使用。所以，我只想改写这个为

However, ++ can be used on its own. So, I would just rewrite this as

j++;

由于它简单地说成

As it simply translates into

j = j + 1;

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