Stack class in java
In java, the package java.util contains a class called Stack which is a child class of Vector class. It implements the standard principle Last-In-First-Out of stack data structure.
The Stack has push method for inesrtion and pop method for deletion. It also has other utility methods.
🔔 In Stack, the elements are added to the top of the stack and removed from the top of the stack.
The Stack class in java has the following constructor.
| S. No. | Constructor with Description |
|---|---|
| 1 |
Stack( )
It creates an empty Stack. |
The Stack class in java has the following methods.
| S.No. | Methods with Description |
|---|---|
| 1 |
Object push(Object element)
It pushes the element onto the stack and returns the same. |
| 2 |
Object pop( )
It returns the element on the top of the stack and removes the same. |
| 3 |
int search(Object element)
If element found, it returns offset from the top. Otherwise, -1 is returned. |
| 4 |
Object peek( )
It returns the element on the top of the stack. |
| 5 |
boolean empty()
It returns true if the stack is empty, otherwise returns false. |
Let's consider an example program to illustrate methods of Stack class.
import java.util.*;
public class StackClassExample {
public static void main(String[] args) {
Stack stack = new Stack();
Random num = new Random();
for(int i = 0; i < 5; i++)
stack.push(num.nextInt(100));
System.out.println("Stack elements => " + stack);
System.out.println("Top element is " + stack.peek());
System.out.println("Removed element is " + stack.pop());
System.out.println("Element 50 availability => " + stack.search(50));
System.out.println("Stack is empty? - " + stack.isEmpty());
}
}
When we execute the above code, it produce the following output.
