arrayImplementation.java

public class arrayImplementation {
    public static class Stack {
        private int[] arr = new int[5];
        private int idx = -1;

        void push(int data) {
            if (isFull()) {
                System.out.println("Stack is full");
                return;
            }
            arr[idx] = data;
            idx++;
        }

        int peek() {
            if (idx == 0) {
                System.out.println("Stack is empty");
                return -1;
            }
            return arr[idx - 1];
        }

        int pop() {
            if (idx == 0) {
                System.out.println("Stack is empty");
                return -1;
            }
            int top = arr[idx - 1];
            arr[idx - 1] = 0;
            idx--;
            return top;
        }

        void display() {
            for (int i = 0; i <= idx - 1; i++) {
                System.out.print(arr[i] + " ");
            }
            System.out.println();
        }

        int size() {
            return idx;
        }

        boolean isEmpty() {
            if (size() == 0) {
                return true;
            }
            return false;
        }

        boolean isFull() {
            if (idx == arr.length) {
                return true;
            }
            return false;
        }
    }

    public static void main(String[] args) {
        Stack st = new Stack();
        st.push(10);
        st.push(20);
        st.push(30);
        st.display();
        System.out.println(st.size());
        st.pop();
        st.display();
        System.out.println(st.size());
        st.push(40);
        st.push(50);
        st.push(60);
        System.out.println(st.isFull());

    }
}