Do you need to solve the problem of finding the middle of the list in one pass when the number of elements is unknown in advance?

public static void main(String[] args) {

    var in = "0 1 2 3 4";
    var scan = new Scanner(in);
    var midAddress = -1;

    while(scan.hasNext()) {
        midAddress++;
        scan.next();
        if (!scan.hasNext()) break;
        scan.next();
    }

    System.out.println("Middle address: " + midAddress);
}