Assstack. java

class Stack {
    
    private int top; 
    private int maxSize; 
    private int[] arr;

    Stack(int maxSize) {
        this.top = -1; 
        this.maxSize = maxSize;
        arr = new int[maxSize];
    }

    public boolean isFull() {
        return top >= (maxSize - 1);
    }

    public boolean push(int data) {
        if (isFull()) {
            return false;
        } else {
            arr[++top] = data;
            return true;
        }
    }

    public int peek() {
        if (isEmpty())
            return Integer.MIN_VALUE;
        else
            return arr[top];
    }

    public void display() {
        if (isEmpty())
            System.out.println("Stack is empty!");
        else {
            System.out.println("Displaying stack elements:");
            for (int index = top; index >= 0; index--) {
                System.out.println(arr[index]);
            }
        }
    }

    public boolean isEmpty() {
        return top < 0;
    }

    public int pop() {
        if (isEmpty())
            return Integer.MIN_VALUE;
        else
            return arr[top--];
    }

    public int getMaxSize() {
        return maxSize;
    }
}
public class StackAssignment{

    public static void main(String args[]) {
            
        Stack stack = new Stack(10);
        stack.push(15);
        stack.push(20);
        stack.push(30);
        stack.push(40);
        
        calculateSum(stack);
            
        System.out.println("Updated stack:");
        stack.display();
    }

    public static void calculateSum(Stack stack) {
        int maxSize = stack.getMaxSize(); // Access maxSize using getter method
        Stack tempStack = new Stack(maxSize); // Temporary stack to reorganize elements

        // Step 1: Calculate the sum of all elements in the original stack
        int sum = 0;
        
        while (!stack.isEmpty()) {
            int element = stack.pop();
            sum += element;
            tempStack.push(element); // Push elements into tempStack
        }
        
        // Step 2: Push the sum to the bottom of the stack
        stack.push(sum);
        
        // Step 3: Restore original stack order with sum at the bottom
        while (!tempStack.isEmpty()) {
            int element = tempStack.pop();
            stack.push(element); // Push elements back to original stack
        }
    }
}