stack.java

package campus;
class Stack {
	static final int MAX = 1000;
	int top;
	int a[] = new int[MAX]; // Maximum size of Stack

	boolean isEmpty()
	{
		return (top < 0);
	}
	Stack()
	{
		top = -1;
	}

	void push(int x)
	{
		if (top >= (MAX - 1)) {
			System.out.println("Stack Overflow");
			
		}
		else {
			a[++top] = x;
			System.out.println(x + " pushed into stack");
			
		}
	}

	int pop()
	{
		if (top < 0) {
			System.out.println("Stack Underflow");
			return 0;
		}
		else {
			int x = a[top--];
			return x;
		}
	}

	int peek()
	{
		if (top < 0) {
			System.out.println("Stack Underflow");
			return 0;
		}
		else {
			int x = a[top];
			return x;
		}
	}
	
	void print(){
	for(int i = top;i>-1;i--){
	System.out.print(" "+ a[i]);
	}
}
}

// Driver code
class StackProgram {
	public static void main(String args[])
	{
		Stack s = new Stack();
		s.push(10);
		s.push(20);
		s.push(30);
		System.out.println(s.pop() + " Popped from stack");
		System.out.println("Top element is :" + s.peek());
		System.out.print("Elements present in stack :");
		s.print();
	}
}