Stack implementation using arrays

				
//**************************************
// Name: Stack implementation using arrays
// Description:performs basic operations on stack.
(please let me know if there are errors)
// By: Creator_1493
//
//This code is copyrighted and has// limited warranties.Please see http://www.Planet-Source-Code.com/vb/scripts/ShowCode.asp?txtCodeId=7025&lngWId=2//for details.//**************************************

// simple operations on stack using array.
 
import javax.swing.JOptionPane;// importing swing class
class stack{
	private static final int size = 20;//declaring and initialising constant 'size' 
	int top;
	int ele[] = new int[size];
	
	stack(){ // initialising stack using constructor of class 
			top = -1; // no elements in stack
	}
	
	
	public void push(){// to insert elements on stack
		String input = JOptionPane.showInputDialog(null, "Enter number you want to insert");
		int info = Integer.parseInt(input);
		if(isfull() ) // checking if stack is full
	JOptionPane.showMessageDialog(null, "stack is full cannot insert", "", JOptionPane.ERROR_MESSAGE);
		else	
	ele[++top] = info; // increment top by one and then, assign data to top index
	} // end of push
	
	private boolean isfull() { // checks if stack is full
		// TODO Auto-generated method stub
		if(top == ele.length - 1)
			return true; // returns true if stack is full
			else
		return false;// returns false if stack is not full
	} // end of is full
	
	
	private boolean isempty(){ // checks if stack is empty
		if (top == -1 )
	return true; // returns true if stack is empty
		else
		return false; // returns false if stack has some elements 
	} // end of isempty
	
	
	public int pop(){// delete an element from top
		int item;
		if(isempty()){ // checking if stack is empty
			 JOptionPane.showMessageDialog(null, "stack is empty cannot delete", "ERROR", JOptionPane.ERROR_MESSAGE);
		 return 0;
		 }
		else
			{
			item = ele[top--]; // decrement top by one
			return item;
			}
	} // end of pop
	
	
	public int peek(){ // to have a look at an element at the top 
		if(isempty() ){ // calls method isempty
			JOptionPane.showMessageDialog(null, "stack is empty", "ERROR", JOptionPane.ERROR_MESSAGE);
		return 0; 
		}
		else
		return ele[top]; // returns element at top
	} // end of peek
	
	
	public void display(){// displays the elements in the stack
		int index = 0;
		String s = "";
		
		if(isempty()) // calls method isempty()
			JOptionPane.showMessageDialog(null, "stack is empty ", "ERROR", JOptionPane.ERROR_MESSAGE);
		else
			{
			while(index <= top)
			 s = s + (index+1) +". "+ele[index++] + "\n";
		
		JOptionPane.showMessageDialog(null, "stack is \n" + s);
		}
	}// end of display
	
 
	public void search(int data){// searches an element in stack
		int index = 0;
		if(isempty()) // calls method is empty
			JOptionPane.showMessageDialog(null, "Stack is empty", "ERROR", JOptionPane.ERROR_MESSAGE);
else{
		while(index <= top){
			if(ele[index] == data){
				JOptionPane.showMessageDialog(null, "Element found at location "+ index);
				break; // if element found then, break out of while loop
			} 
			else
				index++;
		}
		if(index > top) // only case if element is not in stack
		JOptionPane.showMessageDialog(null, "Element " + data +"not found on stack ");
		}
 }// end of search
} // end of class stack
public class Stack_usingarr { // main class 
public static void main(String args[]){
	stack s = new stack(); // creating object of stack class
	int ch = 0;
while(ch < 6){ // while choice is less than six 
	String p = "PRESS";
		String choice = "1.To insert or push\n"+"2.To delete or pop \n"+"3.To search an element\n"+ 
	"4.To traverse stored data \n "+"5.To see element at top of stack"+"\n6.To exit " ;
		
		String c = JOptionPane.showInputDialog(null,p+"\n\n"+choice,"CHOICES",JOptionPane.PLAIN_MESSAGE); // input string 
		ch = Integer.parseInt(c); // converting input string to an integer 
		
		switch(ch){
		case 1:s.push();// calls push method 
			break;
		case 2:int item = s.pop(); // calls pop method 
		JOptionPane.showMessageDialog(null, "Element" + item + " deleted from stack.", "INFORMATION", JOptionPane.INFORMATION_MESSAGE); 
			break;
		case 3:String c1 = JOptionPane.showInputDialog(null,"Enter element you want to search:");
		 int ch1 = Integer.parseInt(c1); 
			 s.search(ch1);// calls search method with parameter as the number to search 
			break;
		case 4:s.display();// calls display method
		break;
		case 5:JOptionPane.showMessageDialog(null, "Element at the top of stack "+s.peek() /*calling peek method*/ ); 
		break;
		case 6:break; // coming out of while loop
			 } // end of switch
		 } // end of while
} //end of main method 
}//end of class stack_usingarr
 
// end