做什么和×0040的标志管这里表示？ [英] What do 0x0040 and pipe sign denote here?

问题描述

下面SIMPLE_EX2用×0040是或运算和整个本提供作为地址来SIMPLE_EX1。我的理解是否正确？

 的#define SIMPLE_EX1（×0040 | SIMPLE_EX2）
 

解决方案

| 不是C.管道标志这是一个逐位或。所以这前pression：

 ×0040 | SIMPLE_EX2
 

只是获取 SIMPLE_EX2 的值，并将它的7 ^个位（右一）为1。

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不太可能的，但要注意，如果 SIMPLE_EX2 本身就是一个前pression与具有较低的precedence比运营商| ，整体前pression可能会错误地PTED间$ p $。例如，如果 SIMPLE_EX2 是 A B：C ，那么 SIMPLE_EX1 变成（×0040 |一）b：？ç这不是我上面写的

Here SIMPLE_EX2 is being ORed with 0x0040 and the whole this providing as an address to SIMPLE_EX1. Is my understanding correct?

#define SIMPLE_EX1  (0x0040 | SIMPLE_EX2) 

解决方案

| is not a pipe sign in C. It's a bit-wise or. So this expression:

0x0040 | SIMPLE_EX2

Simply gets the value of SIMPLE_EX2 and sets it's 7^th bit (from right) to 1.

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Unlikely, but note that if SIMPLE_EX2 itself is an expression with an operator that has lower precedence than |, the overall expression may be interpreted wrongly. For example if SIMPLE_EX2 is a?b:c, then SIMPLE_EX1 becomes (0x0040|a)?b:c which is not what I wrote above.

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