Adding if else for negative numbers

Im trying to add an if else statement so when the profit is negative it tells them its a negative profit and when its positive it tells them its positive. Where would i put the if else statement and how would i format so it works.

import java.util.Scanner;
class Assignment2
{
    public static void main(String[] args) //header of the main method
    {
     Scanner in = new Scanner(System.in);


        String First;
        String Last;
        String StockCode;
        double ShareNumber;
        double StockBuy;
        double StockSell;
        final double charge =.02;

        System.out.println("Enter your First name");
        First = in.nextLine();

        System.out.println("Enter your Last name");
        Last = in.nextLine();

        System.out.println("Enter the stock code");
        StockCode = in.nextLine();

        System.out.println("How much did the stocks cost?");
        StockBuy = in.nextInt();

        System.out.println("How many shares did you buy?");
        ShareNumber = in.nextInt();

        System.out.println("Customer Name:" + First.toUpperCase() + ' ' + Last.toUpperCase());

        System.out.println("Stock Code:" + StockCode );
        System.out.println("Stock Cost:" + ((StockBuy * charge) + (ShareNumber*StockBuy)));

  }
}