homework3

homework3_Array1.java

package homework3;

/**
 * Create array with random fill.
 * Find minimal in array.
 * 
 * Created by Denis on 25.10.2016.
 */
public class Array1 {
    public static void main(String[] args) {
        int n = Helper.inputInt("Input array size:");
        int[] arr = Helper.createRandomArray(n);

        System.out.println("Array: ");
        Helper.printArray(arr);
        System.out.println();

        System.out.println("Minimal:");
        System.out.printf("%4d", Helper.findMinInArray(arr));
    }
}

homework3_Array2.java

package homework3;

/**
 * Calculate sums of rows in 2D array.
 * 
 * Created by Denis on 26.10.2016.
 */
public class Array2 {
    static final int START_RAND = -10;
    static final int END_RAND = 10;
    public static void main(String[] args) {
        int n = Helper.inputInt("Array width :");
        int m = Helper.inputInt("Array height:");
        int[][] arr = new int[m][n];

        for (int i = 0; i < arr.length ; i++) {
            arr[i] = Helper.createRandomArray(arr[i].length, START_RAND, END_RAND);
        }

        System.out.println("Array:");
        for (int i = 0; i < arr.length; i++) {
            Helper.printArray(arr[i]);
            System.out.println();
        }

        System.out.println("Row sums:");
        int[] sum = Helper.sumArrayRows(arr);
        Helper.printArray(sum);
    }
}

homework3_Helper.java

package homework3;

import java.util.InputMismatchException;
import java.util.Scanner;

/**
 * Helper Class for common functions.
 * 
 * Created by Denis on 25.10.2016.
 **/
public class Helper {
    
    public static int inputInt(String prompt) {
        while (true) {
            System.out.print(prompt + " ");
            try {
            Scanner in = new Scanner(System.in);
            return in.nextInt();
            } catch (InputMismatchException ex) {
                System.out.println("Please input integer");
            }
        }
    }

    public static void printArray(int[] arr) {
        for (int x: arr
                ) {
            System.out.printf("%4d", x);
        }
    }

    public static int[] createRandomArray(int n) {
        Random rand = new Random(System.currentTimeMillis());
        int[] arr = new int[n];
        for (int i = 0; i < n; i++) {
            arr[i] = rand.nextInt(n);
        }
        return arr;
    }

    public static int[] createRandomArray(int size, int start, int end) {
        int range = end - start;
        int shift = start;

        int[] arr = new int[size];
        for (int i = 0; i < size; i++) {
            arr[i] = (int) (Math.random() * range) + shift;
        }
        return arr;
    }

    public static int findMinInArray(int[] arr) {
        int min = arr[0];
        for (int i = 0; i < arr.length ; i++) {
            if (min > arr[i]) {
                min = arr[i];
            }
        }
        return min;
    }

    public static int[] sumArrayRows(int[][] arr) {
        int[] result = new int[arr.length];
        for (int i = 0; i < arr.length; i++) {
            for (int j = 0; j < arr[i].length ; j++) {
                result[i] += arr[i][j];
            }
        }
        return result;
    }

}

homework3_MultiplicationTableFunction.java

package homework3;

/**
 * Print Multiplication Table AxB size.
 * 
 * Created by Denis on 25.10.2016.
 */
public class MultiplicationTableFunction {
    public static void main(String[] args) {
        int x = Helper.inputInt("Input A:");
        int y = Helper.inputInt("Input B:");
        System.out.println();
        printMultiplicationTable(x, y);
    }

    static void printMultiplicationTable(int x, int y) {
        for (int i = 1; i <= y; i++) {
            for (int j = 1; j <= x; j++) {
                System.out.printf("%-4d", (i * j));
            }
            System.out.print("\n");
        }
    }
}

homework3_RightTriangleArea.java

package homework3;

/**
 * Calculate Right Triangle Area.
 * 
 * Created by Denis on 25.10.2016.
 */
public class RightTriangleArea {
    public static void main(String[] args) {
        int a = Helper.inputInt("Input A side:");
        int b = Helper.inputInt("Input B side:");
        System.out.println();
        System.out.println("Area of triangle is: " + area(a, b));
    }

    static float area(int a, int b) {
        float s = (float) a * b / 2;
        return s;
    }
}