How to print a stack in Java

Question

I wrote a method that receives a queue as a parameter and then convert this queue into a stack. Now I want to try to print this method in the main to see if it works, but there isn't any toString method for stacks.

I already did some research and tried to convert stacks into arrays, but I can't get it to work. Printing the stack values in Java

How can I do this?

public static void QueueStack(Queue<Integer> q){
    Stack<Integer> stack1 = new Stack<Integer>();
    while(!q.isEmpty()){
        int temp = q.dequeue();
        stack1.push(temp);
    }
    Arrays.toString(stack1.toArray());
}

Possible duplicate of http://stackoverflow.com/a/395403/1980659 — ForguesR, Nov 05 '14 at 03:00
@BatScream I thought I couldn't use Syso for stacks (I learned stacks using arrays and had to write a for to print the values), now I know I can use it to print them out. — user2737948, Nov 05 '14 at 03:32

score 1 · Answer 1 · answered Nov 05 '14 at 03:04

1

Did you try using the Stack classes' toString() method?

e.g.

stack1.toString();

Or was there a specific format you want to print out?

answered Nov 05 '14 at 03:04

HedonicHedgehog

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score 0 · Answer 2 · answered Nov 05 '14 at 04:28

0

You could try the get(int index) method of the Vector class which Stack extends, assuming you don't want to pop the elements from your stack while you print them.

answered Nov 05 '14 at 04:28

pez

3,859
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score 0 · Answer 3 · edited Nov 18 '20 at 20:33

0

You could also do it very similar to how to initialized it.

while(!stack1.isEmpty())
{
   int t = stack1.pop();
   System.out.println(t);
}

edited Nov 18 '20 at 20:33

Peter Mortensen

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answered Feb 28 '17 at 02:28

Conner K. McPhee

49
8

score 0 · Answer 4 · answered Oct 18 '17 at 05:18

0

if (!tack1.isEmpty()) {
    for(Object a : stack1) {
        System.out.println(a);
    }
}

answered Oct 18 '17 at 05:18

Ravshanbek Ahmedov

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score 0 · Answer 5 · answered Jul 29 '20 at 14:41

Here, is a method to convert a given Queue to Stack:

public static void QueueStack(Queue<Integer> queue){

    Stack<Integer> stack = new Stack<>();
    for(Integer in: queue){
        stack.push(in);
    }
    //Here, the output would be same as you inserted elements.As stack uses iterator which prints elements as they are inserted(a bug in stack iteration)
    System.out.println("Stack: "+stack);
    
    //You can use java 8 for-each style as well.
    stack.forEach(System.out::println);
    
    //If you want to traverse stack in LIFO manner..
    while(stack.isEmpty){
    System.ou.println(stack.pop());
    }
    
    //For better performance ArrayDeque<>() is preferred!
    Deque<Integer> stack = new ArrayDeque<Integer>();
    
}

How to print a stack in Java

5 Answers5