Get Maximum Integer Value From Stack

Question

I am new to JAVA and trying to learn. Apologies in advance if my question is basic and not in the correct format.

I am trying to understand how I can get the max int value in a stack please?

private Stack<Integer> stack = new Stack<>();
stack.push(2456785434);
stack.push(1);

essentially, the stack has two integers but I want to return the maximum (2456785434) into a variable. How do I do it please?

Below is the method which is adding the two numbers the user types (these are parsed into int values) - firstNumber and secondNumber.

private int performCalc(int firstNumber, int secondNumber, String op) {
    if (s.equals("+")) {
        return secondNumber + firstNumber;
    } else if (s.equals("-")) {
        return secondNumber - firstNumber;
    } else if (s.equals("*")) {
        return secondNumber * firstNumber;
    } else if (s.equals("/")) {
        return secondNumber / firstNumber;
    } else if (s.equals("%")) {
        return secondNumber % firstNumber;
    } else {
        return 0;
    }
}

Answer 1

You can use the Collections class for this

Integer maxValue = Collections.max(stack)

Answer 2

First of all, 2456785434 is out of range for int which can have a value only from -2147483648 to 2147483647.

You can use the Stream API to find the maximum value from the stack.

import java.util.Comparator;
import java.util.Optional;
import java.util.Stack;

public class Main {
    public static void main(String[] args) {
        Stack<Integer> stack = new Stack<>();
        stack.push(245678544);
        stack.push(1);

        Optional<Integer> max = stack.stream().max(Comparator.naturalOrder());
        System.out.println(max.get());
    }
}

Output:

245678544