Thread: Expression parsing specification?

Basically, I want this:

Code:

if (v1)
  if (va==vb)
    f();

else if (v2)
  if (vc==vd)
    f();

Would I be able to write the above like this instead ?

Code:

if (((v1) && (va==vb)) || ((v2) && (vc==vd)))
  f();

I would assume so (although not tested).

However, in what order is the above guaranteed to be evaluated? Assume v1 & v2 are zero, will the produced code just check v1 and v2, and ignore va,vb,vc and vd? Or will it first check va==vb before checking v1 != 0 ? (ie, will it run exactly the same as first example?)

I want the code to run as quick as possible. I don't want to use multiple if statements and multiple possible function calls, unless there would be a speed improvement in doing so.

Depending on what f() does, it may or may not be the same.

In the first case, f() can potentially be called twice. In the latter edition, it will only ever get called a max of once.