Java: Rotate the stack elements to the left

Java Stack: Exercise-12 with Solution

Write a Java program to rotate the stack elements in the left direction.

Sample Solution:

Java Code:

import java.util.Scanner;
public class Stack {
  private int[] arr;
  private int top;

  // Constructor to initialize the stack
  public Stack(int size) {
    arr = new int[size];
    top = -1;
  }

  // Method to push an element onto the stack
  public void push(int num) {
    if (top == arr.length - 1) {
      System.out.println("Stack is full");
    } else {
      top++;
      arr[top] = num;
    }
  }

  // Method to pop an element from the stack
  public int pop() {
    if (top == -1) {
      System.out.println("Stack Underflow");
      return -1;
    } else {
      int poppedElement = arr[top];
      top--;
      return poppedElement;
    }
  }

  // Method to get the top element of the stack
  public int peek() {
    if (top == -1) {
      System.out.println("Stack is empty");
      return -1;
    } else {
      return arr[top];
    }
  }

  // Method to check if the stack is empty
  public boolean isEmpty() {
    return top == -1;
  }

  public void display() {
    if (top == -1) {
      System.out.println("Stack is empty");
    } else {
      System.out.print("Stack elements: ");
      for (int i = top; i >= 0; i--) {
        System.out.print(arr[i] + " ");
      }
      System.out.println();
    }
  }

  public void rotate_Stack_To_Right(int rotations) {
    if (top == -1) {
      System.out.println("Stack is empty");
      return;
    }
    rotations = rotations % (top + 1);
    for (int i = 0; i < rotations; i++) {
      int temp = arr[top];
      for (int j = top; j > 0; j--) {
        arr[j] = arr[j - 1];
      }
      arr[0] = temp;
    }
  }

  public static void main(String[] args) {
    System.out.println("Initialize a stack:");
    Stack stack = new Stack(7);
    System.out.println("Input some elements on the stack:");
    stack.push(7);
    stack.push(6);
    stack.push(5);
    stack.push(4);
    stack.push(3);
    stack.push(2);
    stack.push(1);
    stack.display();
    System.out.println("\nRotate the stack elements to the left by 2 positions:");
    stack.rotate_Stack_To_Right(2);
    System.out.println("Display the rotated stack:");
    stack.display();
    System.out.println("\nRotate the stack elements to the left by 3 positions:");
    stack.rotate_Stack_To_Right(3);
    System.out.println("Display the rotated stack:");
    stack.display();

  }
}

Sample Output:

Initialize a stack:
Input some elements on the stack:
Stack elements: 1 2 3 4 5 6 7

Rotate the stack elements to the left by 2 positions:
Display the rotated stack:
Stack elements: 3 4 5 6 7 1 2

Rotate the stack elements to the left by 3 positions:
Display the rotated stack:
Stack elements: 6 7 1 2 3 4 5

Flowchart:

Live Demo:

Java Code Editor:

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Java Stack Exercises Next: Remove a specific element from a stack.