basic_stack.java

public class Stackk
{
 static final int MAX=1000;
 int top;
 int starr[] = new int[MAX];
 
 void isEmpty()
 {
 if(top==-1)
 {
 System.out.println("Stack is empty");
 }
 }
 
 public void push(int e)
 {
 if(top>=(MAX-1))
 {
 System.out.println("Stack overflow");
 }
 else
 {
 starr[++top]=e;
 }
 }
 
 int pop()
 {
 if(top<0)
 {
 System.out.println("Stack underfloe");
 return 0;
 }
 else
 {
 int x=starr[top--];
 return x;
 }
 }
 
 int peek()
 {
 if(top<0)
 {
 System.out.println("Stack underflow");
 return 0;
 }
 else
 {
 int a=starr[top];
 return a;
 }
 }

public static void main(String args[])
{
 Stackk s = new Stackk(); 
 s.push(10); 
 s.push(20); 
 s.push(30); 
 System.out.println(s.peek());
 s.pop();
 System.out.println(s.peek());
 
}
}