4.2 java

ъimport java.util.Scanner;
import java.io.*;
public class BinarySearch {
    public static Scanner scan = new Scanner(System.in);
    static Scanner fileScanner;

    public static void main(String[] args) {
        int num;
        int key;
        int[] arr;
        System.out.println("Program implements Binary Search - search of element in array");
        System.out.println("Enter type of input." + '\n' + "1 is console input, 0 is file input.");
        String path;
        boolean chose = choose();
        boolean isIncorrect;
        if (chose) {
            System.out.println("Input size of array:");
            num = inputArraySize();
            do {
                System.out.println("Input array elements:");
                arr = inputArray(num);
                isIncorrect = checkArray(arr);
            } while (!isIncorrect);
            System.out.println("Input number for search:");
            key = inputData();
        } else {
            do {
                path = inputFilePath();
                num = inputSizeOfArrayFromFile(path);
                arr = inputArrayFile(path, num);
                isIncorrect = checkArray(arr);
            } while (!isIncorrect);
            key = inputKeyFromFile(path);
        }
        output(arr, key, num);
    }

    private static void output (int [] arr, int key, int num){
        int result = searchElement(arr, key, 0, num - 1);
        if (result == -1) {
            System.out.println("The element you are looking for is not in the array.");
        } else {
            System.out.println("The item you are looking for is on " + (result + 1) + " place");
        }
    }

    private static boolean choose() {
        int inputNumber = 0;
        boolean isIncorrect;
        final int MIN_NUM = 0;
        final int MAX_NUM = 1;
        do {
            isIncorrect = false;
            try {
                inputNumber = Integer.parseInt(scan.nextLine());
            } catch (Exception e) {
                isIncorrect = true;
                System.out.println("Please, enter a number.");
            }
            if (!isIncorrect && (inputNumber < MIN_NUM || inputNumber > MAX_NUM)) {
                System.out.println("You are out of input range!:");
                isIncorrect = true;
            }
        } while (isIncorrect);
        return inputNumber == 1;
    }
    private static int inputData() {
        int n = 0;
        boolean isIncorrect;
        do {
            isIncorrect = false;
            try {
                n = Integer.parseInt(scan.nextLine());
            } catch (Exception e) {
                isIncorrect = true;
                System.out.println("Please, enter a integer number:");
            }
        } while (isIncorrect);
        return n;
    }

    private static int inputArraySize() {
        boolean isIncorrect;
        final int MIN_SIZE = 2;
        final int MAX_SIZE = 10;
        int num;
        do {
            num = inputData();
            isIncorrect = false;
            if ((num < MIN_SIZE) || (num > MAX_SIZE)) {
                System.out.println("Please, enter a number in the range from 2 to 10:");
                isIncorrect = true;
            }
        } while (isIncorrect);
        return num;
    }

    private static int[] inputArray(int num) {
        int[] arr = new int[num];
        for (int i = 0; i < arr.length; i++)
            arr[i] = inputData();
        return arr;
    }

    private static boolean checkArray (int[] arr) {
        int i = 0;
        boolean ascending = true; // возрастание
        boolean descending = true; // убывание
        while ((i < arr.length - 1) && (descending)) {
            if (arr[i] <= arr[i + 1]) {
                descending = false; // проверка на убывание
            }
            i++;
        }
        i = 0;
        while ((i < arr.length - 1) && (ascending)) {
            if (arr[i] >= arr[i + 1]) {
                ascending = false; // проверка на возрастание
            }
            i++;
        }
        boolean isInCorrect = true;
        if ((!ascending) && (!descending)) {
            System.out.println("Enter a sorted array, since binary search is only possible in such.");
            isInCorrect = false;
        }
        return isInCorrect;
    }

    private static int searchElement(int[] arr, int key, int left, int right) {
        if (left <= right) {
            int mid = left + ((right - left) / 2);
            if (arr[mid] == key) {
                return mid;
            } else if (arr[mid] < key) {
                return searchElement(arr, key, mid + 1, right);
            } else {
                return searchElement(arr, key, left, mid - 1);
            }
        }
        return -1;
    }

    //files
    private static String inputFilePath() {
        String path;
        boolean isIncorrect;
        do {
            isIncorrect = false;
            System.out.println("Input file path:");
            path = scan.nextLine();
            File file = new File(path);
            if (!file.exists()) {
                System.out.println("Wrong way to file.");
                isIncorrect = true;
            }
            if (!file.canRead() && file.exists()) {
                System.out.println("Impossible to read a file.");
                isIncorrect = true;
            }
            if (!file.canWrite() && file.canRead()) {
                System.out.println("Impossible to write a file.");
                isIncorrect = true;
            }
        } while (isIncorrect);
        return path;
    }
    private static int inputSizeOfArrayFromFile(String path) {
        int num = 0;
        boolean isIncorrect;
        final int MIN = 1;
        final int MAX = 10;
        do {
            isIncorrect = false;
            try {
                fileScanner = new Scanner(new File(path));
                num = fileScanner.nextInt();
            } catch (Exception q) {
                isIncorrect = true;
                System.out.println("Check file");
                path = inputFilePath();
            }
            if (!isIncorrect && ((num < MIN) || (num > MAX))) {
                isIncorrect = true;
                System.out.println("Matrix size should be in the range from 2 to 10:");
                path = inputFilePath();
            }
        } while (isIncorrect);
        return num;
    }
    private static int inputKeyFromFile(String path) {
        int num = 0;
        boolean isIncorrect;
        do {
            isIncorrect = false;
            try {
                fileScanner = new Scanner(new File(path));
                fileScanner.nextLine();
                fileScanner.nextLine();
                num = fileScanner.nextInt();
            } catch (Exception q) {
                isIncorrect = true;
                System.out.println("Check file");
                path = inputFilePath();
            }
        } while (isIncorrect);
        return num;
    }

    private static int[] inputArrayFile(String path, int num) {
        boolean isIncorrect;
        int[] arr = new int[num];
        do {
            isIncorrect = false;
            try {
                fileScanner = new Scanner(new File(path));
                fileScanner.nextLine();
                for (int i = 0; (i < arr.length); i++) {
                    arr[i] = fileScanner.nextInt();
                }
            } catch (Exception q) {
                isIncorrect = true;
                System.out.println("Reading of array elements failed.");
                path = inputFilePath();
            }
        } while (isIncorrect);
        return arr;
    }
}