Can someone explain a FSM to me?

[jarf1337]

This is how the FSM machine would process a string composed
of one blank, the digits 9 and 5, two blanks, the letter K, the
digit 9, one blank, and a period. The machine begins in the start state
and process its input one character at a time. When it reads a blank
character from the input, it consumes the blank character and continues
to remain in the start state. In other words, the transition is made
from the start state to start state itself. Next, when it reads a letter,
transition is made from the start state to the build_id state. However,
if the input read is a digit, transition is made from the start state to
the build_num state.

I dont really understand what we are doing here... i'm supposed to create a C program that emulates this but I need to understand the FSM first.

[RyanS]

The description says nothing about what you do when you are in the build_num/build_id state and read in another character?

So as the description stands now, you read in a blank and go back to start, read in a 9 and go to build_num and just stay there.

But I think your description lacks info.