两个等号的线路吗？ [英] Two Equal Signs in One Line?

问题描述

可能有人请解释一下这样做，以及它如何是合法的C code吗？我发现在这个code此行：<一href=\"http://$c$c.google.com/p/com$p$pssion-$c$c/downloads/list\">http://$c$c.google.com/p/com$p$pssion-$c$c/downloads/list,这是维特算法自适应哈夫曼编码的一个 C实现

Could someone please explain what this does and how it is legal C code? I found this line in this code: http://code.google.com/p/compression-code/downloads/list, which is a C implementation of the Vitter algorithm for Adaptive Huffman Coding

ArcChar = ArcBit = 0;

从功能：

void arc_put1 (unsigned bit)
{
    ArcChar <<= 1;

    if( bit )
        ArcChar |= 1;

    if( ++ArcBit < 8 )
        return;

    putc (ArcChar, Out);
    ArcChar = ArcBit = 0;
}

ArcChar是 INT 和ArcBit是 unsigned char型

推荐答案

恩pression值（A = B）是乙，这样你就可以把它们连这种方式。他们还右结合的，所以这是可行的。

The value of the expression (a = b) is b, so you can chain them this way. They are also right-associative, so it all works out.

基本上

ArcChar = ArcBit = 0;

时（约 ¹ ）一样

ArcBit = 0;
ArcChar = 0;

以来的首次assigment的值是分配的值，从而 0 。

至于类型，即使 ArcBit 是 unsigned char型分配的结果将得到扩大至 INT 。

Regarding the types, even though ArcBit is an unsigned char the result of the assignment will get widened to int.

¹ 这不是的究竟的相同，不过，为R ..指出，在下面留言。

¹   It's not exactly the same, though, as R.. points out in a comment below.

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