Lesson009_18_08_19_Arrays

import java.util.Scanner;

public class Lesson009_18_08_19_HomeWork1 {
    private static Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        int option = homeWorkMenu();
        while (option != 0) {       // while the user didn't put '0', keep pop-up the menu!
            switch (option) {
                case 6:
                    option = task6();
                    break;
                case 7:
                    option = task7();
                    break;
                case 8:
                    option = task8();
                    break;
                case 9:
                    option = task9();
                    break;
                case 10:
                    option = task10();
                    break;

                default:
                    System.out.println(option + " is invalid option! try again...\n");
                    option = homeWorkMenu();
            }
        }
    }

    public static int homeWorkMenu() {
        System.out.print("\n...::: MENU :::...\n" +       // A menu for home tasks
                "From presentation '004_18-08-19 arrays' Page 29:\n" +
                "press [6] for task 6\n" +
                "press [7] for task 7\n" +
                "press [8] for task 8\n" +
                "press [9] for task 9\n" +
                "press [10] for task 10\n" +
                "press [0] to end this program.\n" +
                "your option is: ");
        int option = sc.nextInt();
        System.out.println();
        return option;          // back to 'Public Static Void Main();'
    }

    public static int task6() {
        char charArr[] = new char[5];
        int count = 0;
        for (int i = 0; i < charArr.length; i += 1) {
            System.out.print("Enter any char (" + (i + 1) + " of " + charArr.length + "): ");
            charArr[i] = sc.next().charAt(0);
        }
        System.out.print("Enter a char to check: ");
        char check = sc.next().charAt(0);
        for (int i = 0; i < charArr.length; i += 1) {
            count = charArr[i] == check ? count + 1 : count;
        }
        System.out.println("The char: " + check + " appears " + count + " times.");
        int opt = 0;                    // back to home Work Menu.
        return opt = homeWorkMenu();   // back to home Work Menu.
    }

    public static int task7() {
        int arr1[] = new int[5], arr2[] = new int[5];
        for (int i = 0; i < arr1.length; i += 1) {
            System.out.print("Enter any number for array 1 (" + (i + 1) + " of " + arr1.length + "): ");
            arr1[i] = sc.nextInt();
        }       // get 5 numbers into array 1.
        for (int i = 0; i < arr2.length; i += 1) {
            System.out.print("Enter any number for array 2 (" + (i + 1) + " of " + arr2.length + "): ");
            arr2[i] = sc.nextInt();
        }       // get 5 numbers into array 2.

        //int arr1[] = {5,4,3,2,2};
        //int arr2[] = {9,2,5,1,1};
        for (int i = 0; i < arr1.length; i += 1) {
            for (int j = 0; j < arr2.length; j += 1) {
                if (arr1[i] == arr2[j])
                    System.out.println("index arr1:" + i + " and index arr2:" +
                            j + " have same value!");
            }
        }
        int opt = 0;                    // back to home Work Menu.
        return opt = homeWorkMenu();   // back to home Work Menu.
    }

    public static int task8() {
        //int arr[][] = {{1, 2, 3, 4, 5}, {5, 4, 3, 2, 1}};
        int arr[][] = new int[2][5];
        int sum[] = new int[arr[0].length];
        // get 5 numbers into 2 arrays.
        for (int i = 0; i < arr.length; i += 1) {
            for (int j = 0; j < arr[i].length; j += 1) {
                System.out.print("Enter any number for array " + (i + 1) + " (" + (j + 1) + " of " + arr[0].length + "): ");
                arr[i][j] = sc.nextInt();
            }   // end for j loop.
        }   // end for i loop.
        for (int i = 0; i < sum.length; i += 1) {
            sum[i] = arr[0][i] + arr[1][i];
        }
        System.out.println("The sums in array 3 are:");
        for (int i = 0; i < sum.length; i += 1) {
            System.out.print(sum[i] + "  ");
        }
        int opt = 0;                    // back to home Work Menu.
        return opt = homeWorkMenu();   // back to home Work Menu.
    }

    public static int task9() {
        char charArr[] = new char[5];
        boolean check = true;
        System.out.print("Enter any char (1 of " + charArr.length + "): ");
        charArr[0] = sc.next().charAt(0);
        for (int i = 1; i < charArr.length; i += 1) {
            System.out.print("Enter any char (" + (i + 1) + " of " + charArr.length + "): ");
            charArr[i] = sc.next().charAt(0);
            // check if char[i] is the same as char [i-1].
            if (charArr[i] != charArr[i-1]) {
                check = false;
                break;
            }
        }
        System.out.println("The chars in the array are "+(check ? "":"NOT ") + "the same.");
        int opt = 0;                    // back to home Work Menu.
        return opt = homeWorkMenu();    // back to home Work Menu.
    }

    public static int task10() {
        int arr[] = new int [5];
        System.out.print("Please enter a number (1 of " + arr.length + "): ");
        arr[0] = sc.nextInt();
        for (int i = 1; i < arr.length; i += 1) {
            System.out.print("Please enter a number (" + (i + 1) + " of " + arr.length + "): ");
            arr[i] = sc.nextInt();
            if (arr[i] != arr[i - 1])
                break;
        }   // end for i loop
        int opt = 0;                    // back to home Work Menu.
        return opt = homeWorkMenu();    // back to home Work Menu.
    }
}