Integers can be regarded as a series of bits, 0 or 1. Bitwise operators act upon these bits compared to the bit in the same position in the other operand. Signed integers use a bit to indicate the sign, but bitwise operators act on every bit in an integer, so it is usually only sensible to use them on unsigned integers. In the following, all the types are marked as unsigned, so they are treated as not having a sign bit.
The & operator is bitwise AND, which means that each bit in the left-hand operand is compared with the bit in the right-hand operand in the same position. If both are 1, the resultant bit in the same position will be 1; otherwise, the resultant bit is zero:
unsigned int a = 0x0a0a; // this is the binary ...
