C++ Explicit Operators

整理自 Thinking in C++。

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These are keywords for bitwise and logical operators. Non-U.S. programmers without keyboard characters like &, |, ^, and so on, were forced to use C’s horrible trigraphs (比如 ??- 表示 ~；无法想象当时的形势是如何的恶劣以至会设计成这样……), which were not only annoying to type, but obscure when reading. This is repaired in C++ with additional keywords:

Keyword	Meaning
and	&& (logical AND)
or	|| (logical OR)
not	! (logical NOT)
not_eq	!= (logical not-equivalent)
bitand	& (bitwise AND)
and_eq	&= (bitwise AND-assignment)
bitor	| (bitwise OR)
or_eq	|= (bitwise OR-assignment)
xor	^ (bitwise XOR, exclusive OR)
xor_eq	^= (bitwise XOR-assignment)
compl	~ (ones complement)

举个例子：

#include <iostream>
using namespace std;

int main() {
	bool a = true, b = false;
	
	cout << (a and b); // output: 0
	
	// 注意结合律，下式实际是 (cout << a) and b;
	// 然后 cout 的 && 操作符应该是重载了 
	// cout << a and b; // output: 1
}