Switch or array? (C)

[hellrazor]

Say I have a little bit of code. Let's say it's something along the lines of:

unsigned int find_length_of_magnitude(unsigned int magnitude)
{
    unsigned float half = magnitude/2.0f;//Needed?
    unsigned int answer = 1+(6*(half*(magnitude-1)));//Put in return line?
    return answer;
};

Now let's say I want to put in a little (OK, maybe it's big) look-up table, and let's say I don't give a crap about code size (unless it would cause actual problems). Now would a switch table be faster than an array (being pointed to)? Or would a fatty switch table just be useless bloat and bullshit?

 

[W1zzard]

execution time of your code is basically zero. no point writing a lookup table for that.

in general, lookup tables are good, if you can calculate the key into your table quickly.

internally a switch statement often ends up being a lookup into an array with jump adresses (so that's already as expensive as your look up table)

write readable code, let the compiler's optimizer do the work. it's usually smarter than the programmer.

 

[hellrazor]

Yeah, that's what I figured.