If (a && b)

Question

I have the code below:
if (a && b) {
c;
Both expressions a and b are very lengthy and consume much processing power. What I want to know is: if the expression a returns false, does it even check the expression b?
Or is it any better to switch the code to:
if (a) {
if (b) {
c;
Is there any real difference?
Thanks in advance!

Answer 1

if the expression a returns false, does it even check the expression b?easy enough to test
class Testing
  int a = 0;
  int b = 0;
  public Testing()
    if(a() && b()) System.out.println("both true");
    System.out.println("a = "+a);
    System.out.println("b= "+b);
  public boolean a()
    a++;
    return false;
  public boolean b()
    b++;
    return true;
  public static void main( String[] args ){new Testing();}
}if you DO want both evaluated
if(a() & b())