How can I check my byte flag, verifying that a specific bit is at 1 or 0?

Question

I use a byte to store some flag like 10101010, and I would like to know how to verify that a specific bit is at 1 or 0.

Answer 1

Use a bitwise (not logical!) and to compare the value against a bitmask.

if (var & 0x08) {
  /* the fourth bit is set */
}