homework2_ArithmeticProgression.java

package homework2;

import java.util.Scanner;

/**
 * Created by Denis on 18.10.2016.
 */
public class ArithmeticProgression {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.print("Input n: ");
        int n = in.nextInt();

        System.out.println(n * (n + 1) /2);
    }
}

homework2_ArithmeticProgressionRecursion.java

package homework2;

import java.util.Scanner;

/**
 * Created by Denis on 18.10.2016.
 */
public class ArithmeticProgressionRecursion {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.print("Input n: ");
        int n = in.nextInt();

        ArithmeticProgressionRecursion ap = new ArithmeticProgressionRecursion();
        System.out.println(ap.sum(n));
    }

    public int sum(int n){
        return n>1? n+sum(n-1): n;
    }

}

homework2_BartSimpson.java

package homework2;

/**
 * Created by Denis on 18.10.2016.
 */
public class BartSimpson {
    public static void main(String[] args) {
        BartSimpson bart = new BartSimpson();
        
        try {
            int count = Integer.parseInt(args[0]);
            bart.say(count);
        } catch (NumberFormatException | IndexOutOfBoundsException ex) {
            bart.usage();
        }
    }

    public void say(int c) {
        for (int i = 0; i < c; i++){
            System.out.println("i will adopt best practices");
        }
    }

    public void usage() {
        System.out.println("usage: BartSimpson count");
        System.out.println("\tcount: integer number");
    }
}

homework2_DivisibleBy.java

package homework2;

import java.util.Scanner;

/**
 * Created by Denis on 18.10.2016.
 */
public class DivisibleBy {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.print("Input n: ");
        int n = in.nextInt();
        System.out.print("Input m: ");
        int m = in.nextInt();

        for (int i = 1; i <= n; i++) {
            if ((i % m) == 0) System.out.println(i);
        }
    }
}

homework2_MultiplicationTable.java

package homework2;

/**
 * Created by Denis on 18.10.2016.
 */
public class MultiplicationTable {

    public static void main(String[] args) {
        for (int i = 1; i < 10; i++) {
            for (int j = 1; j < 10; j++) {
                System.out.printf("%4d", i*j);
            }
            System.out.println();
        }
    }
}

homework2_MultiplicationTableHash.java

package homework2;

/**
 * Created by Denis on 18.10.2016.
 */
public class MultiplicationTableHash {
    public static void main(String[] args) {
        for (int i = 1; i < 10; i++) {
            for (int j = 1; j < 10; j++) {
                if (i < j) {
                    System.out.printf("%4s", "#");
                } else {
                    System.out.printf("%4d", i*j);
                }
            }
            System.out.println();
        }
    }
}

homework2_NullToTwentyEvens.java

package homework2;

/**
 * Created by Denis on 18.10.2016.
 */
public class NullToTwentyEvens {
    public static void main(String[] args) {
        for (int i = 0; i <= 20; i+=2) {
            System.out.println(i);
        }
    }
}

homework2_OddEven.java

package homework2;

/**
 * Created by Denis on 18.10.2016.
 */
public class OddEven {
    public static void main(String[] args) {
        int a = (int) (Math.random() * 100);
        System.out.println(a);

        if ((a % 2) == 0) {
            System.out.println("even");
        } else {
            System.out.println("odd");
        }
    }
}

homework2_TenToNull.java

package homework2;

/**
 * Created by Denis on 18.10.2016.
 */
public class TenToNull {
    public static void main(String[] args) {
        int i = 10;
        while (true) {
            System.out.print(i--);
            if (i < 0)  break;
            System.out.print(", ");
        }
    }
}