removed duplciated data-structures

DataStructures/Stacks/Stacks.java

@@ -53,16 +53,18 @@ class Stack{
 	 * @return value popped off the Stack
 	 */
 	public int pop(){
-		if(isEmpty()){ //Checks for an empty stack
-			System.out.println("The stack is already empty");
-			return -1;
+		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;
 		}
-        
-        return stackArray[top--];
 	}
 
 	/**