Help needed please. Why I'm trying to use the top method in order to print the first element of my list. why is it not working?

import java.util.Stack; public class MyDS { Stack s; Stack minStack; Stack maxStack; public int top; public MyDS(){ s = new Stack(); minStack = new Stack(); maxStack = new Stack(); } //top method public top() { return stack[t]; } //Size method public int size() { return int top = -1; } //Empty method public boolean isEmpty() { return t == -1; } // Push Method public void push(int k){ if(minStack.isEmpty()){ minStack.push(k); }else if(k <= minStack.peek()){ minStack.push(k); } if(maxStack.isEmpty()){ maxStack.push(k); }else if(k >= maxStack.peek()){ maxStack.push(k); } s.push(k); } // Pop Method public void pop(){ int popped; if(!s.isEmpty()){ popped = s.pop(); }else{ popped = -1; } if(popped == min()){ minStack.pop(); } if(popped == max()){ maxStack.pop(); } } // Min Method public int min(){ if(!minStack.isEmpty()){ return minStack.peek(); }else{ return Integer.MIN_VALUE; } } // Max Method public int max(){ if(!maxStack.isEmpty()){ return maxStack.peek(); }else{ return Integer.MAX_VALUE; } } }

import java.util.Stack; public class DS { static Stack stack; static Stack minStack; static Stack maxStack; public DS(){ stack = new Stack(); minStack = new Stack(); maxStack = new Stack(); } // Push Method public void push(int k){ stack.push(k); if(!minStack.isEmpty()){ minStack.push(Math.min(k, minStack.peek())); }else{ minStack.push(k); } if(!maxStack.isEmpty()){ maxStack.push(Math.max(k, maxStack.peek())); }else{ maxStack.push(k); } } // Pop Method public void pop(){ if(!stack.isEmpty() && !minStack.isEmpty() && !maxStack.isEmpty()){ stack.pop(); minStack.pop(); maxStack.pop(); } } // Find Min public int findMin(){ if(!minStack.isEmpty()){ return minStack.peek(); } return Integer.MIN_VALUE; } // Find Max public int findMax(){ if(!maxStack.isEmpty()){ return maxStack.peek(); } return Integer.MAX_VALUE; } public static void main(String[] args) { DS ds = new DS(); System.out.println("size is " + stack.size()); System.out.println("Is Empty? " + stack.isEmpty()); System.out.println("Push 7, 6, 5: "); ds.push(7); ds.push(6); ds.push(5); System.out.println("Size now is " + stack.size()); System.out.println("Is Empty? now " + stack.isEmpty()); System.out.println("top element is "+ stack.top()); //This line says cannot find symbol. why? System.out.println("S1: " + stack); System.out.println("S2: " + minStack); System.out.println("S3: " + maxStack); System.out.println("Min till now: " + ds.findMin()); System.out.println("Max till now: " + ds.findMax()); System.out.println("Push 4, 3: "); ds.push(4); ds.push(3); System.out.println(stack); System.out.println(minStack); System.out.println(maxStack); System.out.println("Min till now: " + ds.findMin()); System.out.println("Max till now: " + ds.findMax()); System.out.println("1 pop(): "); ds.pop(); System.out.println("Min till now: " + ds.findMin()); System.out.println("Max till now: " + ds.findMax()); System.out.println("1 pop(): "); ds.pop(); System.out.println("Min till now: " + ds.findMin()); System.out.println("Max till now: " + ds.findMax()); } }