解引用和后缀的precedence [英] Precedence of dereference and postfix

问题描述

当我用K＆放阅读TCPL; R，我只是不明白两位前pressions：

When I read the TCPL by K&R, I just couldn't understand two expressions:

*p++ = val;  /*push val onto stack */

下面是我的想法：

• 解引用和后缀具有相同的precedence，和结合性是从右到左，所以

• dereference and postfix has the same precedence, and associativity is right to left,so

* P ++ = VAL 可能与相同*（P +）= VAL ，因为指针通常是下一个位置的顶部，所以在这个code，首先，因为括号的对增加1，所以p是两个单位以上的当前顶部，但不是一个单位以上的当前顶部，其中VAL应！ THX

*p++ = val maybe the same with *(p++) = val, because the pointer usually is the next position to the top , so in this code, p increase 1 first because of the parenthesis, so the p is the two units above the current top ,but not the one unit above the current top ,where the val should be!!! Thx

推荐答案

在preFIX递增/递减和间接引用运营商都是平等的precedence，但后缀运算符更高，所以 * p ++ 相同 *（p ++），这就像写 * p = VAL; p ++;

The prefix increment/decrement and dereference operators are equal precedence, but the postfix operator is higher, so *p++ is the same as *(p++), which is like writing *p = val; p++;

如果你写（* P）++ = VAL ，它不会编译，因为你会试图分配一个值到一个数字。

If you wrote (*p)++ = val, it wouldn't compile, as you'd be trying to assign a value to a number.

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