Ignoring part of code after compilation

Question

My code looks something like this

while(!eof)
{
   if(A)
     doSomething;
   if(B)
     doSomething;
}

A and B are parameters from comand line. There may be also more parameters. I have struct of Bools, in which are all posible parameters and for every parameter, it determines if he exist or not.

Can i make compiler to not read the some part of the code?

I mean, in this code he will check for existence of B every iteration. What i want to achieve is that he will only check once

 if(B)
    doSomething;

I want this just to optimalize my program and i NEED to have both ifs in one cycle.

Read [this](http://stackoverflow.com/q/5431941/2173917) first. — Sourav Ghosh, Apr 27 '15 at 10:32
It is not clear what you are asking. What do you mean by "compiler to not read" and "i NEED to have both ifs in one cycle"? Seems contradictory . — DrKoch, Apr 27 '15 at 10:35
Check the topic of Conditional Compilation. https://msdn.microsoft.com/en-us/library/ew2hz0yd.aspx — Veverke, Apr 27 '15 at 10:35
"*if he didnt get parameter B he will never, or max 1 time do*" - What? Please explain — Spikatrix, Apr 27 '15 at 10:35
I think OP wants to check for A and B only once, not every time in main loop. — holgac, Apr 27 '15 at 11:20

score 3 · Answer 1 · answered Apr 27 '15 at 10:35

Frankly speaking, Ignoring part of code after compilation makes no sense. The code is already compiled. However. you can skip the execution of certain part of code using conditional statements, like if, else-if etc.

FWIW, "Command line parameters" are supplied and considered at run-time. There is no way you can decide (conditional compilation) based on that at compile-time.

However, if you want, you can always check the number of arguments (argc) supplied through command line and take action based on that.

Alternatively, if you wanted to have a conditional compilation, reading something about #ifdef/#ifndef may help.

Ignoring part of code after compilation

1 Answers1