Converting loops (Java Beginner question)

Question

Does Converting between loops always works like this? or there is some situation that it does not? and what is the fastest way to check while I\'m solving a question like th

Answer 1

The other members have covered the execution semantics. But I wanted to add the variable scoping semantics.

In Java, you can do this:

for (Iterator i = localList.iterator(); i.hasNext(); ) {
  String element = i.next();
  if (...) {
    i.remove();
  }
}

for (Iterator i = importList.iterator(); i.hasNext(); ) {
  String element = i.next();
  if (...) {
    i.remove();
  }
}

Where the variable 'i' is used twice.

In order to translate that to while loops with correct scoping, you need to use additional code blocks:

{
  Iterator i = localList.iterator();
  while (i.hasNext()) {
    String element = i.next();
    if (...) {
      i.remove();
    }
  }
}

{
  Iterator i = importList.iterator();
  while (i.hasNext()) {
    String element = i.next();
    if (...) {
      i.remove();
    }
  }
}

Note how the additional { ... } allows you to use the same variable names.

While not as important in Java, in languages like C++, the scoping has important ramifications beyond just being able to use the same variable names. Object destruction, IIA (instantiation is acquisition) etc are affected by the additional block.