They can be any values in the domain of the function.
what is a program x and y
write a c program to accept a number and generate a square root cube and exponential values
That would be the domain.
the inputs and outputs of digital IC can take only two values 0 or 1. But the inputs and outputs of an analog IC can take infinite number of values.
"logic" can refer to program logic (the steps or algorithm to how a program works), or Boolean logic (the values true or false or the operations that act on those values, such as AND, OR, NOT, and XOR [exclusive OR]).