What is the difference of signed and unsigned integer?
It is the interpretation of the first bit of the integer number been represented. If it is signed, the first bit is 0 means it is a positive number, 1 means it is negative. If it is unsigned, the first bit is just another bit, either to add (1) or not to add (0) 2n to the value of the number. n is the bit location, 0 based counted from right to left.
