I see and I forget, I hear and I remember, I do and I understand是孔子说的吗？出处在哪里?

I'm trying to get my head around the use of the tilde operator, and associated functions. My 1st question is why does I() need to be used to specify arithmetic operators? For example, these 2 plots

I tested and it matches test, TEST, and teSt. But I have never seen this before. What does the ? before i mean? I saw this here.

Só para complementar: colocar os ++ antes da variável tem o nome de operação de pré incremento e colocar os ++ depois da variável tem o nome de operação de pós incremento. Também é valido para operações de subtração: --i (pré decremento) e i-- (pós decremento).

i不是问题。毕竟书名可以用cite，强调可以用em。而汉字也没斜着写的传统，重新定义i也不是啥问题。 问题出在小图标上。好好的汉字不用。非要跟着不识字的西方人搞什么图标。搞图标也就算了，图标用的unicode是不知道什么鬼字符，而不是对应意思的汉字。这严重损害了 accessability，伤害了中国 ...

В связи с наступлением на нас шаблонов в С++, рекомендуется писать в циклах ++i а не i++. Это связано с тем, что прединкремент для классов обычно реализуется проще, чем постинкремент (как минимум, не надо хранить старое ...

I've seen them both being used in numerous pieces of C# code, and I'd like to know when to use i++ and when to use ++i? (i being a number variable like int, float, double, etc).

Possible Duplicate: Is there a performance difference between i++ and ++i in C++? Is there a reason some programmers write ++i in a normal for loop instead of writing i++?

In the latter two cases the ++i looks like an attempt to produce smarty-looking code. Am I overseeing something? Is there a reason to use ++i instead of i++ in the latter two cases?

@aelgoa +1, as this has nearly full coverage in other languages, ++i is always a best practice unless a particular language has explicitly worse performance. I've heard people argue it is negligible, but not always. For instance with server-side javascript not just generating a page, you may well be looping quickly over a one liner millions of times. This can cut your per-loop overhead by ~1/2 ...