Real world use cases of bitwise operators - Stack Overflow
I've used bitwise operations in implementing a security model for a CMS. It had pages which could be accessed by users if they were in appropriate groups. A user could be in multiple groups, so we needed to check if there was an intersection between the users groups and the pages groups. So we assigned each group a unique power-of-2 identifier ...
c++ - Performance wise, how fast are Bitwise Operators vs. Normal ...
2013年12月5日 · Bitwise operations are much faster. This is why the compiler will use bitwise operations for you. Actually, I think it will be faster to implement it as: ~i & 1 Similarly, if you look at the assembly code your compiler generates, you may see things like x ^= x instead of x=0. But (I hope) you are not going to use this in your C++ code.
c++ - How to set, clear, and toggle a single bit - Stack Overflow
This can cause all manner of subtle bugs because of implicit integer promotion or bitwise operations on signed types. thingstate = ThingFlag1 >> 1 will for example invoke implementation-defined behavior. thingstate = (ThingFlag1 >> x) << y can invoke undefined behavior. And so on. To be safe, always cast to an unsigned type. –
Are there any Bitwise Operator Laws? - Stack Overflow
2012年10月7日 · Bitwise operations that are just a boolean operator applied between corresponding bits of the operands follow laws analogous to the laws of Boolean algebra, for example: AND (&) : Commutative, Associative, Identity (0xFF), Annihilator (0x00), Idempotent
boolean - What are bitwise operators? - Stack Overflow
In digital computer programming, a bitwise operation operates on one or more bit patterns or binary numerals at the level of their individual bits. It is a fast, primitive action directly supported by the processor, and is used to manipulate values for comparisons and calculations. operations: bitwise AND. bitwise OR. bitwise NOT. bitwise XOR ...
Can you use bitwise operators with enum classes without casting?
2020年10月23日 · Bit operations on Enum. 10. ... Conveniently defining bitwise operators for enums for creating bit flags. 1.
Implementing if - else if using bitwise operators - Stack Overflow
2013年6月2日 · Assume that the value of test is 1 or 0. Here I can implement the following if statement using bitwise operators as below.
Bitwise and in place of modulus operator - Stack Overflow
2010年6月19日 · Using bitwise_and, bitwise_or, and bitwise_not you can modify any bit configurations to another bit configurations (i.e. these set of operators are "functionally complete"). However, for operations like modulus, the general formula would be necessarily be quite complicated, I wouldn't even bother trying to recreate it.
bit manipulation - Bitwise Operations in Ada - Stack Overflow
2013年8月21日 · Implementing bitwise operators for integer would not have been difficult at all. C has the philosophy of letting the programmer do anything that might make sense. Ada's philosophy is more about catching errors as early as possible. You can do bitwise operations on integers in Ada; you just can't do it the particular way you're trying to do it.
Are the results of bitwise operations on signed integers defined?
By the way, note that per 6.2.6.1, negative zero, if it exists, is required to behave identically to ordinary zero as an operand to bitwise operations: Where an operator is applied to a value that has more than one object representation, which object representation is used shall not affect the value of the result. –
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