If / Else statement, how to say "DoNothing" or "Continue"

I have an IF / ELSE statement, although I would like to know how to tell the "else" part to do nothing if it is true. e.g.:

if(x == x) 
 //run calc.exe

else
//DoNothing

Or I am write in saying that if I just remove the else statement, it will continue anyway if the if condition is not matched?