Question

What is BODMAS and why is it useful in programming?

Answer 1

http://www.easymaths.com/What_on_earth_is_Bodmas.htm:

What do you think the answer to 2 + 3 x 5 is?

Is it (2 + 3) x 5 = 5 x 5 = 25 ?

or 2 + (3 x 5) = 2 + 15 = 17 ?

BODMAS can come to the rescue and give us rules to follow so that we always get the right answer:

(B)rackets (O)rder (D)ivision (M)ultiplication (A)ddition (S)ubtraction

According to BODMAS, multiplication should always be done before addition, therefore 17 is actually the correct answer according to BODMAS and will also be the answer which your calculator will give if you type in 2 + 3 x 5 .

Why it is useful in programming? No idea, but i assume it’s because you can get rid of some brackets? I am a quite defensive programmer, so my lines can look like this:

result = (((i + 4) - (a + b)) * MAGIC_NUMBER) - ANOTHER_MAGIC_NUMBER; 

with BODMAS you can make this a bit clearer:

result = (i + 4 - (a + b)) * MAGIC_NUMBER - ANOTHER_MAGIC_NUMBER; 

I think i’d still use the first variant – more brackets, but that way i do not have to learn yet another rule and i run into less risk of forgetting it and causing those weird hard to debug errors?

Just guessing at that part though.

Mike Stone EDIT: Fixed math as Gaius points out