Random Implementation of Zellers

Context

Some code, my friend asked for...

Snippet

public class code {

    public static int zeller(int q, int m, int year) {
        if (m < 3) {
            m+=12;
        }
        int K = year % 100;
        int J = year / 100;
        return (q+(13*(m+1))/5+K+K/4+J/4+5*J)%7;
    }

    public static String determineDay(int h){
        switch (h) {
            case 0:
                return "Sunday";
            case 1:
                return "Monday";
            case 2:
                return "Tuesday";
            case 3:
                return "Wednesday";
            case 4:
                return "Thursday";
            case 5:
                return "Friday";
            case 6:
                return "Saturday";
            default:
                return "Invalid Output";
        }
    }

    public static void main(String[] args) {
        System.out.println(determineDay(zeller(25, 12, 2025)));
    }
}