Sequential circuits: state

Mathematical functions have no state: inputs combined to produce output, no memory

C/C++ functions may have state: store data from 1 call to another

static variables

objects store values in data members

State of a running program

Values of variables

Values of registers

Contents of stack

Address of current instruction

Hibernate laptop

Save state of entire machine, including all programs

Sequential logic circuits

Previous history is used together with inputs to produce output

We don't care HOW previous value was obtained

State encoded in bits

Finite number of bits, so finite number of states