What is the difference between signed and unsigned variables?

Question

I have seen these mentioned in the context of C and C++, but what is the difference between signed and unsigned variables?

Answer 1

Signed variables use one bit to flag whether they are positive or negative. Unsigned variables don't have this bit, so they can store larger numbers in the same space, but only nonnegative numbers, e.g. 0 and higher.

For more: Unsigned and Signed Integers