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c++operatorslogicadditionor-operator

Should I prefer addition or logical OR operator if both would give the same result?

Should I prefer + (addition) operator or | (or) operator if both would give the same result?

I understand that addition and logical OR are different things. But they sometimes do the same thing in some macros, especially when playing with bytes and bits. Which one should I prefer in this case?

Example:

uint8_t Byte1 = 0x02;   // 0000 0010
uint8_t Byte2 = 0x80;   // 1000 0000
uint16_t Word1, Word2;  // 0000 0010 1000 0000 = 640 = 0x0280

Word1 = (Byte1 << 8) + Byte2;
Word2 = (Byte1 << 8) | Byte2;

std::cout << "Word1 = " << Word1 << std::endl;
std::cout << "Word2 = " << Word2 << std::endl;

Output:

Word1 = 640
Word2 = 640

Solution

  • When manipulating bit patterns, logical operators are appropriate. When manipulating numeric values, arithmetic operators are appropriate.