Java SE: How to iterate Stack 博客分类： JavaSE JavaStackIterate

How to iterate a stack in Java?

    1> Pitfall: Using iterator to iterate Stack

@Test
public void iterateTest() {
    Stack<String> stack = new Stack<String>();
    stack.push("I");
    stack.push("Love");
    stack.push("You");
    for (String str : stack) {
        System.out.println(str);
    }
}
// Output:
I
Love
You

    Contrary to our expectation, It is iterated like a Queue instead of a Stack. 

    It's a bug listed in BugList matained by Oracle and won't be fixed because of capatibility.

    2> The correct way to iterate stack is:

@Test
public void iterateTest2() {
  Stack<String> stack = new Stack<String>();
  stack.push("I");
  stack.push("Love");
  stack.push("You");
  while (!stack.isEmpty()) {
      System.out.println(stack.pop());
  }
}
//Output:
You
Love
I

 

 

Reference Links:

1) http://www.tigraine.at/2010/05/12/never-assume-stack-iterators-in-java

2) http://bugs.java.com/bugdatabase/view_bug.do?bug_id=4475301