STACK USING ARRAY IN JAVA

/*
TOPIC:STACK USING ARRAY.
DATE:2/8/2012
*/
import java.io.*;
class Stack
{
int stk[]=new int[10];
int top;
Stack()
{
top=-1;
}
void push(int i)
{
if(top==9)
System.out.println("Stack Overflow!");
else
stk[++top]=i;
}


int pop()
{
if(this.isEmpty())
{
System.out.println("underflow");
return 0;}
else
{
System.out.println(stk[top]);

return stk[top--];
}}
boolean isEmpty()
{
if(top<0)
return true;
else
return false;
}
}

class main
{
 public static void main(String args[]) throws IOException
{
InputStreamReader isr=new InputStreamReader(System.in);
BufferedReader br=new BufferedReader(isr);
Stack s=new Stack();
int ch;
do
{
System.out.println("MENU");
System.out.println("1.PUSH");
System.out.println("2.POP");
System.out.println("3.isEmpty");
System.out.println("4.DISPLAY");
System.out.println("5.EXIT");
System.out.println("ENTER A CHOICE");
ch=Integer.parseInt(br.readLine());
switch(ch)
{
case 1:

int no;
System.out.println("enter no.");
no=Integer.parseInt(br.readLine());
s.push(no);
break;

case 2:
int m=s.pop();
System.out.println(m+" has been popped out");
break;
case 3:
System.out.println("Empty: "+ s.isEmpty());
break;

case 4:
for(int i=0;i<=s.top;i++)
System.out.print(s.stk[i]+" ");
break;

case 5:
break;
}
}while (ch!=5);

}}
/*
OUTPUT:
MENU
1.PUSH
2.POP
3.isEmpty
4.DISPLAY
5.EXIT
ENTER A CHOICE
1
enter no.
25
MENU
1.PUSH
2.POP
3.isEmpty
4.DISPLAY
5.EXIT
ENTER A CHOICE
1
enter no.
26
MENU
1.PUSH
2.POP
3.isEmpty
4.DISPLAY
5.EXIT
ENTER A CHOICE
1
enter no.
65
MENU
1.PUSH
2.POP
3.isEmpty
4.DISPLAY
5.EXIT
ENTER A CHOICE
4
25      26      65      MENU
1.PUSH
2.POP
3.isEmpty
4.DISPLAY
5.EXIT
ENTER A CHOICE
3
Empty: false
MENU
1.PUSH
2.POP
3.isEmpty
4.DISPLAY
5.EXIT
ENTER A CHOICE
2
65
65 has been popped out
MENU
1.PUSH
2.POP
3.isEmpty
4.DISPLAY
5.EXIT
ENTER A CHOICE
2
26
26 has been popped out
MENU
1.PUSH
2.POP
3.isEmpty
4.DISPLAY
5.EXIT
ENTER A CHOICE
2
25
25 has been popped out
MENU
1.PUSH
2.POP
3.isEmpty
4.DISPLAY
5.EXIT
ENTER A CHOICE
2
underflow
0 has been popped out
MENU
1.PUSH
2.POP
3.isEmpty
4.DISPLAY
5.EXIT
ENTER A CHOICE
5
MENU
1.PUSH
2.POP
3.isEmpty
4.DISPLAY
5.EXIT
ENTER A CHOICE
1
enter no.
25
MENU
1.PUSH
2.POP
3.isEmpty
4.DISPLAY
5.EXIT
ENTER A CHOICE
1
enter no.
26
MENU
1.PUSH
2.POP
3.isEmpty
4.DISPLAY
5.EXIT
ENTER A CHOICE
1
enter no.
65
MENU
1.PUSH
2.POP
3.isEmpty
4.DISPLAY
5.EXIT
ENTER A CHOICE
4
25      26      65      MENU
1.PUSH
2.POP
3.isEmpty
4.DISPLAY
5.EXIT
ENTER A CHOICE
3
Empty: false
MENU
1.PUSH
2.POP
3.isEmpty
4.DISPLAY
5.EXIT
ENTER A CHOICE
2
65
65 has been popped out
MENU
1.PUSH
2.POP
3.isEmpty
4.DISPLAY
5.EXIT
ENTER A CHOICE
2
26
26 has been popped out
MENU
1.PUSH
2.POP
3.isEmpty
4.DISPLAY
5.EXIT
ENTER A CHOICE
2
25
25 has been popped out
MENU
1.PUSH
2.POP
3.isEmpty
4.DISPLAY
5.EXIT
ENTER A CHOICE
2
underflow
0 has been popped out
MENU
1.PUSH
2.POP
3.isEmpty
4.DISPLAY
5.EXIT
ENTER A CHOICE
5
*/