C++ Primer, Fifth Edition

Bitwise Shift Operators

We have already used the overloaded versions of the >> and << operators for input and output. The built-in meaning of these operators is that they perform a bitwise shift on their operands. They yield a value that is a copy of the (possibly promoted) left-hand operand with the bits shifted as directed by the right-hand operand. The right-hand operand must not be negative and must be a value that is strictly less than the number of bits in the result. Otherwise, the operation is undefined. The bits are shifted left (<<) or right (>>). Bits that are shifted off the end are discarded:

The left-shift operator (the << operator ...