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 can be 0, positive or negative.

Unsigned variables can be 0 or positive.

Unsigned variables are used sometimes because more bits can be used to represent the actual value. Giving you a larger range. Also you can ensure that a negative value won't be passed to your function for example.