Basic Java

//1. to convert fahrenheit to celcius
class FahrenheitToCelsius {
    public static void main(String[] args) {
        int satF;
        int sunF;
        satF=72;
        sunF=78;
        double satC=(5D/9)*(satF-32);
        double sunC=(5D/9)*(sunF-32);
        System.out.println("Weekend Averages");
        System.out.println("Saturday: "+satC);
        System.out.println("Sunday: "+sunC);
    }
}
//2. input from user and convert fahrenheit to celsius
import java.util.Scanner;
class FahrenheitToCelsius {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.print("Enter a Fahrenheit value: ");
        int fahrenheit  = input.nextInt();
        input.nextLine();
        double celsius = (5.0/9)*(fahrenheit-32);
        System.out.println("Fahrenheit: "+fahrenheit);
        System.out.println("Celsius: "+celsius); 
        if (fahrenheit >= 70)
            System.out.println("Yay! A good day to go outside");
    }
}
//3. Formatted and Unformatted  total (rounds off upto 2 decimals)
import java .util.Scanner;
import java.text.NumberFormat;
public class currency {
    public static void main(String[] args) {
        int items;
        double itemCost, total;
        Scanner input = new Scanner(System.in);
        System.out.print("Enter the number of items: ");
        items = input.nextInt();
        System.out.print("Cost per item: ");
        itemCost = input.nextDouble();
        total = items*itemcost;
        System.out.println();
        System.out.println("Unformatted Total: " + total);
        NumberFormat currencyFormat = NumberFormat.getCurrencyInstance();
        System.out.println("Formatted Total: " + currencyFormat.format(total));
    }
}

//4. comparison test
public class ComparisonTest {
    public static void main(String[] args) {
        String x = "hello";
        String y = "hell0";
        if (x.compareTo(y)>0){
            System.out.println("x is greater than y"); 
            System.out.println("x: "+x);
            System.out.println("y: "+y);
        }
    }
}