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Wikipedia, the one true source of knowledge, states:
On most older microprocessors, bitwise operations are slightly faster than addition and subtraction operations and usually significantly faster than multiplication and division operations. On modern architectures, this is not the case: bitwise operations are generally the same speed as addition (though still faster than multiplication).
Is there a practical reason to learn bitwise operation hacks or it is now just something you learn for theory and curiosity?
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Examples of uses of bitwise operations include encryption, compression, graphics, communications over ports/sockets, embedded systems programming and finite state machines. A bitwise operator works with the binary representation of a number rather than that number's value.
The Bitwise Algorithms is used to perform operations at the bit-level or to manipulate bits in different ways. The bitwise operations are found to be much faster and are sometimes used to improve the efficiency of a program. For example: To check if a number is even or odd.
No. First, using bitwise operators in contrast to logical operators is prone to error (e.g., doing a right-shift by 1 is NOT equivalent to multiplying by two). Second, the performance benefit is negligible (if any).
Bitwise operations are incredibly simple and thus usually faster than arithmetic operations.
Bitwise operations are worth studying because they have many applications. It is not their main use to substitute arithmetic operations. Cryptography, computer graphics, hash functions, compression algorithms, and network protocols are just some examples where bitwise operations are extremely useful.
The lines you quoted from the Wikipedia article just tried to give some clues about the speed of bitwise operations. Unfortunately the article fails to provide some good examples of applications.
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Bitwise operations are still useful. For instance, they can be used to create "flags" using a single variable, and save on the number of variables you would use to indicate various conditions. Concerning performance on arithmetic operations, it is better to leave the compiler do the optimization (unless you are some sort of guru).
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