Merge pull request #672 from hayderhassan/separate-stacks-class to fix #667

Separate stacks class

DataStructures/Stacks/StackArray.java

@@ -0,0 +1,152 @@
+/**
+ * This class implements a Stack using a regular array.
+ * <p>
+ * A stack is exactly what it sounds like. An element gets added to the top of
+ * the stack and only the element on the top may be removed. This is an example
+ * of an array implementation of a Stack. So an element can only be added/removed
+ * from the end of the array. In theory stack have no fixed size, but with an
+ * array implementation it does.
+ *
+ * @author Unknown
+ */
+public class StackArray {
+
+    /**
+     * Main method
+     *
+     * @param args Command line arguments
+     */
+    public static void main(String[] args) {
+        // Declare a stack of maximum size 4
+        StackArray myStackArray = new StackArray(4);
+
+        // Populate the stack
+        myStackArray.push(5);
+        myStackArray.push(8);
+        myStackArray.push(2);
+        myStackArray.push(9);
+
+        System.out.println("*********************Stack Array Implementation*********************");
+        System.out.println(myStackArray.isEmpty()); // will print false
+        System.out.println(myStackArray.isFull()); // will print true
+        System.out.println(myStackArray.peek()); // will print 9
+        System.out.println(myStackArray.pop()); // will print 9
+        System.out.println(myStackArray.peek()); // will print 2
+    }
+
+    /**
+     * The max size of the Stack
+     */
+    private int maxSize;
+
+    /**
+     * The array representation of the Stack
+     */
+    private int[] stackArray;
+
+    /**
+     * The top of the stack
+     */
+    private int top;
+
+    /**
+     * Constructor
+     *
+     * @param size Size of the Stack
+     */
+    public StackArray(int size) {
+        maxSize = size;
+        stackArray = new int[maxSize];
+        top = -1;
+    }
+
+    /**
+     * Adds an element to the top of the stack
+     *
+     * @param value The element added
+     */
+    public void push(int value) {
+        if (!isFull()) { // Checks for a full stack
+            top++;
+            stackArray[top] = value;
+        } else {
+            resize(maxSize * 2);
+            push(value); // don't forget push after resizing
+        }
+    }
+
+    /**
+     * Removes the top element of the stack and returns the value you've removed
+     *
+     * @return value popped off the Stack
+     */
+    public int pop() {
+        if (!isEmpty()) { // Checks for an empty stack
+            return stackArray[top--];
+        }
+
+        if (top < maxSize / 4) {
+            resize(maxSize / 2);
+            return pop();// don't forget pop after resizing
+        } else {
+            System.out.println("The stack is already empty");
+            return -1;
+        }
+    }
+
+    /**
+     * Returns the element at the top of the stack
+     *
+     * @return element at the top of the stack
+     */
+    public int peek() {
+        if (!isEmpty()) { // Checks for an empty stack
+            return stackArray[top];
+        } else {
+            System.out.println("The stack is empty, cant peek");
+            return -1;
+        }
+    }
+
+    private void resize(int newSize) {
+        // private int[] transferArray = new int[newSize]; we can't put modifiers here !
+        int[] transferArray = new int[newSize];
+
+        // for(int i = 0; i < stackArray.length(); i++){ the length isn't a method .
+        for (int i = 0; i < stackArray.length; i++) {
+            transferArray[i] = stackArray[i];
+            stackArray = transferArray;
+        }
+        maxSize = newSize;
+    }
+
+    /**
+     * Returns true if the stack is empty
+     *
+     * @return true if the stack is empty
+     */
+    public boolean isEmpty() {
+        return (top == -1);
+    }
+
+    /**
+     * Returns true if the stack is full
+     *
+     * @return true if the stack is full
+     */
+    public boolean isFull() {
+        return (top + 1 == maxSize);
+    }
+
+    /**
+     * Deletes everything in the Stack
+     * <p>
+     * Doesn't delete elements in the array
+     * but if you call push method after calling
+     * makeEmpty it will overwrite previous
+     * values
+     */
+    public void makeEmpty() { // Doesn't delete elements in the array but if you call
+        top = -1;             // push method after calling makeEmpty it will overwrite previous values
+    }
+}

DataStructures/Stacks/StackArrayList.java

@@ -0,0 +1,95 @@
+import java.util.ArrayList;
+
+/**
+ * This class implements a Stack using an ArrayList.
+ * <p>
+ * A stack is exactly what it sounds like. An element gets added to the top of
+ * the stack and only the element on the top may be removed.
+ * <p>
+ * This is an ArrayList Implementation of a stack, where size is not
+ * a problem we can extend the stack as much as we want.
+ *
+ * @author Unknown
+ */
+public class StackArrayList {
+
+    /**
+     * Main method
+     *
+     * @param args Command line arguments
+     */
+    public static void main(String[] args) {
+        
+        StackArrayList myStackArrayList = new StackArrayList();
+        
+        myStackArrayList.push(5);
+        myStackArrayList.push(8);
+        myStackArrayList.push(2);
+        myStackArrayList.push(9);
+
+        System.out.println("*********************Stack List Implementation*********************");
+        System.out.println(myStackArrayList.isEmpty()); // will print false
+        System.out.println(myStackArrayList.peek()); // will print 9
+        System.out.println(myStackArrayList.pop()); // will print 9
+        System.out.println(myStackArrayList.peek()); // will print 2
+        System.out.println(myStackArrayList.pop()); // will print 2
+    }
+
+    /**
+     * ArrayList representation of the stack
+     */
+    private ArrayList<Integer> stackList;
+
+    /**
+     * Constructor
+     */
+    public StackArrayList() {
+        stackList = new ArrayList<>();
+    }
+
+    /**
+     * Adds value to the end of list which
+     * is the top for stack
+     *
+     * @param value value to be added
+     */
+    public void push(int value) {
+        stackList.add(value);
+    }
+
+    /**
+     * Pops last element of list which is indeed
+     * the top for Stack
+     *
+     * @return Element popped
+     */
+    public int pop() {
+
+        if (!isEmpty()) { // checks for an empty Stack
+            int popValue = stackList.get(stackList.size() - 1);
+            stackList.remove(stackList.size() - 1);  // removes the poped element from the list
+            return popValue;
+        }
+
+        System.out.print("The stack is already empty!");
+        return -1;
+    }
+
+    /**
+     * Checks for empty Stack
+     *
+     * @return true if stack is empty
+     */
+    public boolean isEmpty() {
+        return stackList.isEmpty();
+    }
+
+    /**
+     * Top element of stack
+     *
+     * @return top element of stack
+     */
+    public int peek() {
+        return stackList.get(stackList.size() - 1);
+    }
+}

DataStructures/Stacks/Stacks.java

@@ -1,240 +0,0 @@
-import java.util.ArrayList;
-
-/**
- * This class implements a Stack using two different implementations.
- * Stack is used with a regular array and Stack2 uses an ArrayList.
- *
- * A stack is exactly what it sounds like. An element gets added to the top of
- * the stack and only the element on the top may be removed. This is an example
- * of an array implementation of a Stack. So an element can only be added/removed
- * from the end of the array. In theory stack have no fixed size, but with an
- * array implementation it does.
- *
- * @author Unknown
- *
- */
-class Stack{
-	/** The max size of the Stack */
-	private int maxSize;
-	/** The array representation of the Stack */
-	private int[] stackArray;
-	/** The top of the stack */
-	private int top;
-
-	/**
-	 * Constructor
-	 *
-	 * @param size Size of the Stack
-	 */
-	public Stack(int size){
-		maxSize = size;
-		stackArray = new int[maxSize];
-		top = -1;
-	}
-
-	/**
-	 * Adds an element to the top of the stack
-	 *
-	 * @param value The element added
-	 */
-	public void push(int value){
-		if(!isFull()){ //Checks for a full stack
-			top++;
-			stackArray[top] = value;
-		}else{
-			resize(maxSize*2);
-                        push(value);// don't forget push after resizing
-		}
-	}
-
-	/**
-	 * Removes the top element of the stack and returns the value you've removed
-	 *
-	 * @return value popped off the Stack
-	 */
-	public int pop(){
-		if(!isEmpty()){ //Checks for an empty stack
-			return stackArray[top--];
-		}
-
-		if(top < maxSize/4){
-			resize(maxSize/2);
-			return pop();// don't forget pop after resizing
-		}
-		else{
-			System.out.println("The stack is already empty");
-			return -1;
-		}
-	}
-
-	/**
-	 * Returns the element at the top of the stack
-	 *
-	 * @return element at the top of the stack
-	 */
-	public int peek(){
-		if(!isEmpty()){ //Checks for an empty stack
-			return stackArray[top];
-		}else{
-			System.out.println("The stack is empty, cant peek");
-			return -1;
-		}
-	}
-
-	private void resize(int newSize){
-		//private int[] transferArray = new int[newSize]; we can't put modifires here !
-                int[] transferArray = new int[newSize];
-
-		//for(int i = 0; i < stackArray.length(); i++){ the length isn't a method .
-                for(int i = 0; i < stackArray.length; i++){
-			transferArray[i] = stackArray[i];
-			stackArray = transferArray;
-		}
-		maxSize = newSize;
-	}
-
-	/**
-	 * Returns true if the stack is empty
-	 *
-	 * @return true if the stack is empty
-	 */
-	public boolean isEmpty(){
-		return(top == -1);
-	}
-
-	/**
-	 * Returns true if the stack is full
-	 *
-	 * @return true if the stack is full
-	 */
-	public boolean isFull(){
-		return(top+1 == maxSize);
-	}
-
-	/**
-	 * Deletes everything in the Stack
-	 *
-	 * Doesn't delete elements in the array
-	 * but if you call push method after calling
-	 * makeEmpty it will overwrite previous
-	 * values
-	 */
-	public void makeEmpty(){ //Doesn't delete elements in the array but if you call
-		top = -1;			 //push method after calling makeEmpty it will overwrite previous values
-	}
-}
-
-/**
- * This is an ArrayList Implementation of stack, Where size is not
- * a problem we can extend the stack as much as we want.
- *
- * @author Unknown
- *
- */
-class Stack2{
-		/** ArrayList representation of the stack */
-		ArrayList<Integer> stackList;
-
-		/**
-		 * Constructor
-		 */
-		Stack2(){
-			stackList=new ArrayList<>();
-		}
-
-		/**
-		 * Adds value to the end of list which
-		 * is the top for stack
-		 *
-		 * @param value value to be added
-		 */
-		void push(int value){
-			stackList.add(value);
-		}
-
-		/**
-		 * Pops last element of list which is indeed
-		 * the top for Stack
-		 *
-		 * @return Element popped
-		 */
-		int pop(){
-
-			if(!isEmpty()){ // checks for an empty Stack
-
-				int popValue=stackList.get(stackList.size()-1);
-				stackList.remove(stackList.size()-1);  //removes the poped element from the list
-				return popValue;
-			}
-			else{
-				System.out.print("The stack is already empty  ");
-				return -1;
-			}
-
-		}
-
-		/**
-		 * Checks for empty Stack
-		 *
-		 * @return true if stack is empty
-		 */
-		boolean isEmpty(){
-			if(stackList.isEmpty())
-				return true;
-
-			else return false;
-
-		}
-
-		/**
-		 * Top element of stack
-		 *
-		 * @return top element of stack
-		 */
-		int peek(){
-			return stackList.get(stackList.size()-1);
-		}
-	}
-
-/**
- * This class implements the Stack and Stack2 created above
- *
- * @author Unknown
- *
- */
-public class Stacks{
-	/**
-	 * Main method
-	 *
-	 * @param args Command line arguments
-	 */
-	public static void main(String args[]){
-			Stack myStack = new Stack(4); //Declare a stack of maximum size 4
- 		//Populate the stack
- 		myStack.push(5);
- 		myStack.push(8);
-  		myStack.push(2);
-  		myStack.push(9);
-
-		System.out.println("*********************Stack Array Implementation*********************");
-  		System.out.println(myStack.isEmpty()); //will print false
-  		System.out.println(myStack.isFull()); //will print true
-  		System.out.println(myStack.peek()); //will print 9
-  		System.out.println(myStack.pop()); //will print 9
-  		System.out.println(myStack.peek()); // will print 2
-
-		Stack2 myStack2 = new Stack2(); //Declare a stack of maximum size 4
-  		//Populate the stack
- 		myStack2.push(5);
-		myStack2.push(8);
- 		myStack2.push(2);
- 		myStack2.push(9);
-
- 		System.out.println("*********************Stack List Implementation*********************");
- 		System.out.println(myStack2.isEmpty()); //will print false
- 		System.out.println(myStack2.peek()); //will print 9
- 		System.out.println(myStack2.pop()); //will print 9
- 		System.out.println(myStack2.peek()); // will print 2
- 		System.out.println(myStack2.pop()); //will print 2
-	}
-}

README-ko.md

@@ -179,7 +179,7 @@ and much more...|                                                    and more...
 ------|-----|
 [노드 스택](DataStructures/Stacks/NodeStack.java)|[AVL 트리](DataStructures/Trees/AVLTree.java)|
 [연결리스트 스택](DataStructures/Stacks/StackOfLinkedList.java)|[이진 트리](DataStructures/Trees/BinaryTree.java)|
-[스택](DataStructures/Stacks/Stacks.java)|And much more...|
+[스택](DataStructures/Stacks)|And much more...|
 
 * [Bags](DataStructures/Bags/Bag.java)
 * [Buffer](DataStructures/Buffers/CircularBuffer.java)

README.md

@@ -181,7 +181,8 @@ Stacks|Trees|
 ------|-----|
 [Node Stack](DataStructures/Stacks/NodeStack.java)|[AVL Tree](DataStructures/Trees/AVLTree.java)|
 [Stack of Linked List](DataStructures/Stacks/StackOfLinkedList.java)|[Binary Tree](DataStructures/Trees/BinaryTree.java)|
-[Stacks](DataStructures/Stacks/Stacks.java)|And much more...|
+[Array Stack](DataStructures/Stacks/StackArray.java)|And much more...|
+[ArrayList Stack](DataStructures/Stacks/StackArrayList.java)||
 
 * [Bags](DataStructures/Bags/Bag.java)
 * [Buffer](DataStructures/Buffers/CircularBuffer.java)