语言是否需要preIncrement(++ x)和postIncrement(x ++) [英] whether a language needs preIncrement (++x) and postIncrement (x++)

问题描述

我从未在实际代码中看到预增和后增的用例.我最常看到的地方是拼图.
我的看法是，它引入了更多的混乱，而不是有用的.

I have never seen the usecase for pre-increment and post-increment in actual code. The only place i see them most often are puzzles.
My opinion is, it introduces more confusion rather than being useful.

• 是否有任何实际的用例场景

• 不能通过使用+ =

• is there any real use case scenario for this

• can't this can be done by using +=

y = x++

y = x
x += 1

推荐答案

这只是编写相同内容的一种较短的方法，只会使那些不了解C的人感到困惑.^(a) .可以用相同的论据来代替:

It's just a shorter way of writing the same thing and it's only confusing to those who don't deeply understand C ^(a). The same argument could be made for replacing:

for (i = 0; i < 10; i++)
    printf ("%d\n", i);

具有:

i = 0;
while (i < 10) {
    printf ("%d\n", i);
    i = i + 1;
}

因为任何for也可以用while完成，或者:

since any for can also be done with while, or:

i = 0;
loop: if (i < 10) {
    printf ("%d\n", i);
    i = i + 1;
    goto loop;
}

因为任何循环构造都可以根据条件和goto构建.但是(我希望)你不会那样做，对吗?

since any loop construct can be built out of conditions and goto. But (I'm hoping) you wouldn't do that, would you?

^(a)有时我想以简单的陈述和副作用向我的学生解释这一点，这使C代码更简洁，可读性通常没有损失或损失很小.

^(a) I sometimes like to explain this to my students as simple statements and side effects, something that allows C code to be more succinct with usually no or minimal loss in readability.

对于声明:

y = x++;

声明将x分配给y，其副作用是x之后会增加. ++x是相同的，只是副作用是事先发生的.

the statement is assigning x to y with the side effect that x is incremented afterwards. ++x is the same, it's just that the side effect happens beforehand.

类似地，赋值的副作用是它将赋值为赋值，这意味着您可以执行以下操作:

Similarly, the side effect of an assignment is that it evaluates as the value assigned, meaning you can do things like:

while ((c = getchar()) != -1) count++;

并使之类似于:

42;

完全有效，但无用的C语句.

perfectly valid, but useless, C statements.

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