unsigned

The unsigned keyword is used to modify the char, int, and long types in order to define unsigned versions of these types.

The unsigned types can store the full 8-, 16-, and 32-bits of data without requiring that one of the bits be used to represent the sign of the value. This doubles the range of positive values that can be stored in each of these variable types.

unsigned char uc = 0xff;
unsigned int ui = 0xffff;
unsigned long ul = 0xffffffff;