PROGRAM TO DISPLAY STACK OPERATIONS

[project topics]

Code:

import java.io.*;
import java.util.*;
class Demo
{
static final int max=4;
       int a[]=new int[max];
        int top;
      Demo()
{
top=-1;
}
void push(int item)
{
if(top==max)
               System.out.println("Stack is full");
else
              a[++top]=item;
}
int pop()
{
          if(top==-1)
              return 0;
else
return a[top--];
}


void display()
{
System.out.println("New Stack Is:");
for(int i=0;i<=top;i++)
System.out.println(a[i]);
}
}
class Stacks
{
public static void main(String args[])throws IOException
{
DataInputStream dim=new DataInputStream(System.in);
Demo s=new Demo();
int op;
do
{
          System.out.println("\n1.push\n2.pop\n3.display4.exit\n");
               op=Integer.parseInt(dim.readLine());
               switch(op)
{
               case 1:System.out.println("enter item to push");
                             int n=Integer.parseInt(dim.readLine());  
                            s.push(n);
                            break;
              case 2:int f=s.pop();
                             if(f==0)
                             {
                                 System.out.println("empty stack:");
                             }
                             else
                             {
                              System.out.println("poped element is"+f);
                          }
                             break;
case 3:s.display();break;
case 4:break;
default:System.out.println("wrong choice?");
}
}while(op!=4);
}
}

OUTPUT
E:\ 5BCA-B\lijo\java >java Stacks
1.push
2.pop
3.display
4.exit
1
enter item to push
1
1.push
2.pop
3.display
4.exit
1
enter item to push
2
1.push
2.pop
3.display
4.exit
3
New Stack Is:
1
2
1.push
2.pop
3.display
4.exit
2
poped element is2
1.push
2.pop
3.display
4.exit

3
New Stack Is:
1
1.push
2.pop
3.display 4.exit 4