DataStructure/Stack.java at master · manumaini/DataStructure · GitHub

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public class Stack {

	int[] arr ;
	int capacity;
	int top;

	Stack(int size){

		arr= new int[size];
		capacity = size;
		top = -1;

	}

	public void push(int data) {

		if(isFull()) {
			System.out.print("stack overflow");
			return;
		}

		arr[++top] = data;

	}

	public int pop() {

		if(isEmpty()) {
			System.out.print("stack underflow");
			return -1;
		}

		int data = arr[top--];
		return data;


	}

	public void printStack() {

		for(int i = 0 ; i <= top ; i++) {
			System.out.print(" "+arr[i]);
		}

	}


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

	public boolean isEmpty() {
		return top == -1 ;
	}


	public static void main(String args[]) {

		Stack stack = new Stack(5);

		stack.push(1);
		stack.push(2);
		stack.push(3);

		stack.printStack();

		int data = stack.pop();

		if(data == 3) {
			System.out.print("\nwoohoo we have done it\n");
		}

		stack.printStack();

	}
}