If-else vs switch – Which is better?

This is complete garbage. Even allowing for it being a microbenchmark, each iteration contains a System.out.println that takes thousands of times more cycles than the conditional.

For most applications, the choice between an if-ladder and a switch statement should be driven mostly by legibility and not performance. If performance is at stake, I would look for I/O first, memory access patterns second, and instruction sequencing last.

Often times, there is a third choice: polymorphism using interfaces.

Consider an example from the article:

public static void testIfElse(int jumpLabel) {

if(1 == jumpLabel) {

    System.out.println("1");

} else if(2 == jumpLabel) {

    System.out.println("2");

} else if(3 == jumpLabel) {

    System.out.println("3");

} else if(4 == jumpLabel) {

    System.out.println("4");

}

// Removed for simplicity

else {

    System.out.println("default");

}

}

Why not implement this as follows:

public interface IfElse {

   public void testIfElse();

}

public class JumpLabelDefault implements IfElse {

   public void testIfElse() {

      System.out.println("Default"); 

   }

}

public class JumpLabel1 implements IfElse {

   public void testIfElse() {

      System.out.println("1");

   }

}

...

Then, to do the same test, you have this function:

public static void testIfElse(IfElse obj) {

   obj.testIfElse();

}

This is faster than either an if-else statement or a switch statement and you can easily add new cases by creating new objects without needing to change the previous code.

I'm not sure why this option is not included in the article.

I don't understand how he gets his conclusion. The switch statements ran faster by a factor of two or more. Isn't that a significant improvement in performance?

I have now become accustomed to using COND which I would find a way to emulate if I had to program in another language. I find too many errors in simple if statements.

Plus, the switch seems to be inviting trouble, considering Duff's Device.

Oh, and I consider performance better if i get the correct result.

lambdas in an array or hash :)

Sometimes I have to use a hack in javascript to create a quick switch, instead of if...else:

  if(n==0) dir="north"
  else if(n==1) dir="east"
  else if(n==2) dir="south"
  else if(n==3) dir="west"

or switch:

  switch(n){
    case 0: dir="north"; break;
    case 1: dir="east"; break;
    case 2: dir="south"; break;
    case 3: dir="west"; break; 
  }

I'll use:

  dir=["north","east","south","west"][n]

I hope you find it useful in some cases too

Code that test the finite switch:

3. for (int i = 0; i < iteration; i++) {

4. testSwitchFinite(i);

5. }

Once i > 5, testSwitchFinite will always skip to default. This function doesn't even test the switch properly.

Something like testSwitchFinite(i%5+1) would have made more sense (for the finite switch and if-else.)