Comprehensive Overview of the Java Stack Data Structure
Java Stack Overview
Introduction to Stack
A Stack is a data structure that follows the Last In, First Out (LIFO) principle, meaning that the last element added to the stack is the first one to be removed.
Key Concepts
- Push: Adding an element to the top of the stack.
- Pop: Removing the top element from the stack.
- Peek: Viewing the top element without removing it.
- Empty: Checking if the stack has no elements.
Java Stack Class
The Stack
class in Java is part of the java.util
package. It extends the Vector
class, which means it inherits methods from Vector
.
Basic Operations
Checking if Stack is Empty
boolean isEmpty = stack.isEmpty(); // Returns false
Peeking the Top Element
int top = stack.peek(); // Returns 20 without removing it
Popping Elements
int topElement = stack.pop(); // Removes 30
Pushing Elements
stack.push(10);
stack.push(20);
stack.push(30);
Creating a Stack
Stack<Integer> stack = new Stack<>;
Example Usage
import java.util.Stack;
public class StackExample {
public static void main(String[] args) {
Stack<String> stack = new Stack<>;
stack.push("Apple");
stack.push("Banana");
stack.push("Cherry");
System.out.println("Top element: " + stack.peek()); // Cherry
System.out.println("Popped element: " + stack.pop()); // Cherry
System.out.println("Is stack empty? " + stack.isEmpty()); // false
}
}
Conclusion
The Stack
class provides a simple yet effective way to manage data with LIFO behavior in Java. It is useful in various applications such as expression evaluation, backtracking algorithms, and undo mechanisms in software.