JAVA PROGRAM OF STACK INTERFACE

//DEFINE AN INTEGER STACK INTERFACE

interface IntStack
{
void push(int item); //store an item
int pop(); //retrieve an item
}

//program of implements of IntStack interface ....

class Stack implements IntStack
{
private int stck[];
private int tos;

Stack(int size)
{
stck=new int[size];
tos= -1; //it indicate that stack is empty
}

public void push(int item)
{
if(tos==stck.length-1)
System.out.println("Stack is full");
else
stck[++tos]=item;

}

public int pop()
{
if(tos<0)
{
System.out.println("Stack is underflow");
return 0;
}
else
return stck[tos--];
}
}

class CallStack
{
public static void main(String ar[])
{
Stack s1=new Stack(10);
Stack s2=new Stack(20);

System.out.println("First Stack");
for(int i=0;i<10;i++)
{
s1.push(i);
System.out.println(s1.pop());
}
System.out.println(" ");
System.out.println("Second Stack");
for(int i=0;i<20;i++)
{
s2.push(i);
System.out.println(s2.pop());
}
}

}

 OUTPUT OF ABOVE PROGRAM---