class Stack {
private int[] arr; // array to store stack elements
private int top; // index of the top element
private int capacity; // maximum size of the stack
// Constructor
public Stack(int size) {
arr = new int[size];
capacity = size;
top = -1; // empty stack
}
// Push operation
public void push(int value) {
if (isFull()) {
System.out.println("Stack overflow! Cannot push " + value);
return;
}
arr[++top] = value;
System.out.println(value + " pushed to stack.");
}
// Pop operation
public int pop() {
if (isEmpty()) {
System.out.println("Stack underflow! Nothing to pop.");
return -1;
}
return arr[top--];
}
// Peek operation
public int peek() {
if (isEmpty()) {
System.out.println("Stack is empty!");
return -1;
}
return arr[top];
}
// Check if stack is empty
public boolean isEmpty() {
return top == -1;
}
// Check if stack is full
public boolean isFull() {
return top == capacity - 1;
}
// Display stack elements
public void display() {
if (isEmpty()) {
System.out.println("Stack is empty!");
return;
}
System.out.print("Stack elements: ");
for (int i = 0; i <= top; i++) {
System.out.print(arr[i] + " ");
}
System.out.println();
}
// Main method for testing
public static void main(String[] args) {
Stack stack = new Stack(5);
stack.push(10);
stack.push(20);
stack.push(30);
stack.display();
System.out.println("Top element: " + stack.peek());
stack.pop();
stack.display();
stack.pop();
stack.pop();
stack.pop(); // underflow example
}
}
