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Update LinkedStack.java #4

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f92b348
Update LinkedStack.java
Doyle1771 Apr 6, 2017
7be6eac
Update LinkedStack.java
Doyle1771 Apr 10, 2017
ce36138
Merge pull request #7 from srdelisser/Doyle1771-patch-4
Doyle1771 Apr 10, 2017
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71 changes: 60 additions & 11 deletions LinkedStack.java
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Original file line number Diff line number Diff line change
Expand Up @@ -3,12 +3,25 @@
*
* @author Marcel Turcotte ([email protected])
*/
import java.util.Iterator;

public class LinkedStack<E> implements Stack<E> {
public class LinkedStack<E> implements Stack<E>{

// Objects of the class Elem are used to store the elements of the
// stack.

//Don't think these are actually needed, if we do it recursively I think I get it
// private int count = 0;
// private int counter=1;
// LinkedStack<E> a = new LinkedStack<E>(); //this is the original stack
// LinkedStack<E> tmp = new LinkedStack<E>();
// LinkedStack<E> tmptwo = new LinkedStack<E>();
//LinkedStack<E> b = new LinkedStack<E>(); //this is the original stack
// LinkedStack<E> temp = new LinkedStack<E>();
// LinkedStack<E> temptwo= new LinkedStack<E>();
//LinkedStack<E> tempthree = new LinkedStack<E>();
E end;

private int size;
private static class Elem<T> {
private T value;
private Elem<T> next;
Expand Down Expand Up @@ -46,6 +59,7 @@ public void push(E value) {
}

top = new Elem<E>(value, top);
size++;
}

/** Returns the top element, without removing it.
Expand Down Expand Up @@ -78,23 +92,59 @@ public E pop() {
/** Removes the top element of the stack. The element inserted at
* the bottom of the stack.
*/

//not sure best way to go about this
//start by poping the top, adding to new temp stack, iterating over remaining stack to add to temp
//then replace old stack with temp stack

public void roll() {

throw new UnsupportedOperationException("IMPLEMENT THIS METHOD");

if(top!=null){
roll(pop());//start recursion
}
}

private void roll(E b){
if (top==null){
push(b);
}else{
E temp = pop();
roll(b);
push(temp);
}
}
/** Removes the botttom element. The element is inserted on the
* top of the stack.
*/

//ok so make new temp stack, iterate from second to end
//push first onto temp
//replace old with temp
//jk that didn't work I'll try recursion and actually read the instructions f/n/o
public void unroll() {

throw new UnsupportedOperationException("IMPLEMENT THIS METHOD");

end=null;
if(top!=null){
E temporary=pop();
if(top==null){
push(temporary);
}else{
push(temporary);
unroller();
push(end);
}
}
}

// E finally;
private void unroller(){
E now = pop();
E temporary = pop();
if(top!=null){
push(temporary);
unroller();
push(now);
}else{
end=temporary;
push(now);
}
}
/** Returns a string representation of the stack.
*
* @return a string representation
Expand All @@ -116,5 +166,4 @@ public void unroll() {

return stackStr.toString();
}

}