uses for state machines [closed]

Answer 1

Good answers. Here's my 2 cents. Finite State Machines are a theoretical idea that can be implemented multiple different ways, such as a table, or as a while-switch (but don't tell anybody it's a way of saying goto horrors). It is a theorem that any FSM corresponds to a regular expression, and vice versa. Since a regular expression corresponds to a structured program, you can sometimes just write a structured program to implement your FSM. For example, a simple parser of numbers could be written along the lines of:

/* implement dd*[.d*] */
if (isdigit(*p)){
    while(isdigit(*p)) p++;
    if (*p=='.'){
        p++;
        while(isdigit(*p)) p++;
    }
    /* got it! */
}

You get the idea. And, if there's a way that runs faster, I don't know what it is.