Prog3/Numbers.java

public class Numbers {

    private int number;

    public static void main(String[] args) {
        for (int i = 1; i <= 200; i++) {
            if (isDivisibleBy(5, i)) {
                System.out.println(i + " ist durch " + 5 + " teilbar!");
            } else if (lastDigitIs(9, i)) {
                System.out.println(i + " endet auf " + 9);
            } else if (sumWithPredecessorIsDivisibleBy(3, i)) {
                System.out.println(i + " und " + (i - 1) + " addiert ergeben " + (2*i-1) + " und " + (2*i-1) + " ist durch " + 3 + " teilbar");
            }
        }
    }

    public static boolean isDivisibleBy( int divisor, int number) {
        if (number % divisor == 0 ) {
            return true;
        } else {
            return false;
        }
    }

    public static boolean lastDigitIs( int digit , int number) {
        if (number % 10 == digit) {
            return true;
        } else {
            return false;
        }
    }

    public static int sumWithPredecessor(int number) {
        return 2 * number -1;
    }

    public static boolean sumWithPredecessorIsDivisibleBy( int divisor, int number) {
        int s = sumWithPredecessor(number);
        if (isDivisibleBy(divisor, s)) {
            return true;
        } else {
            return false;
        }
    }
}