Charismatic's questions

package homeWork5;

import java.io.*;
import java.util.*;

public class WarAndWorldService1 {
    public void runSet() {
        try {
            FileReader fileReader = new FileReader("Module/Война и мир_книга.txt");
            Set<String> wordsWeNeed = new HashSet<>();
            int symbol;
            StringBuilder builder = new StringBuilder();
            while ((symbol = fileReader.read()) != -1) {
                if (symbol != ' ' && symbol != '\n' && symbol != ',' && symbol != '.' && symbol != '!' && symbol != ')' && symbol != '"'
                        && symbol != ':' && symbol != ';' && symbol != '?' && symbol != '*' && symbol != '(') {
                    builder.append((char) symbol);
                } else {
                    wordsWeNeed.add(builder.toString());
                    builder.setLength(0);
                }
            }
                wordsWeNeed.add(builder.toString());
                System.out.println(wordsWeNeed);
                System.out.println(wordsWeNeed.size());
            } catch(FileNotFoundException f){
                System.out.println("Ошибка. Файл не найден.");
            } catch(IOException e){
                System.out.println("Ошибка чтения файла.");
            }
        }
    }

问题是如何首先将文本文件数据转换为字符串。例如：

while((symbol = fileReader.read()) != -1) {
builder.append((char) symbol);
}
String result = builder.toString;

然后从这一行中提取单词（没有标点符号等）。我知道有这样的事情：

 String[] resultArr = result.split(" ");

但据我了解，在这种情况下，需要使用正则表达式。问题是，我可以从没有正则表达式的字符串中提取“纯”词吗？

public class Student<NU,N,A,R,O> {
    private final NU nu;
    private final N n;
    private final A a;
    private final R r;
    private final O o;

    public Student(NU nu, N n, A a, R r, O o) {
        this.nu = nu;
        this.n = n;
        this.a = a;
        this.r = r;
        this.o = o;
    }

    public N getN() {
        return n;
    }
    public A getA() {
        return a;
    }
    public R getR() {
        return r;
    }

    @Override
    public String toString() {
        return "\n Student[" +
                "Порядковый номер = " + nu +
                ", Имя = '" + n + '\'' +
                ", Возраст = " + a +
                ", Оценка = " + r +
                ", Олимпядник = " + o +
                ']' ;
    }
}

COMPARATOR 
public class StudentsComparatorsAgeAndRating implements Comparator<Student<Integer,String,Integer,Double,Boolean>> {

    @Override
    public int compare(Student o1, Student o2) {
        if (!(o1.getA().equals(o2))) {
            return (Integer)o1.getA() - (Integer)o2.getA();
        }
        return 0;
    }
}
public class StudentsComparatorsName implements Comparator<Student<Integer, String, Integer, Double, Boolean>> {

    @Override
    public int compare(Student o1, Student o2) {
        return (Integer)o1.getN().toString().length() - (Integer) o2.getN().toString().length();
    }
}
public class StudentsComparatorsRating implements Comparator<Student<Integer, String, Integer, Double, Boolean>> {
    @Override
    public int compare(Student o1, Student o2) {
        BigDecimal bd = BigDecimal.valueOf((Double)o1.getR());
        BigDecimal bd1 = BigDecimal.valueOf((Double)o2.getR());
        return bd1.compareTo(bd);
    }
}

问题是，我可以在没有类型转换的情况下比较泛型吗？

public class DataContainer<T> {
    T[] data;
    DataContainer(T[] data) {
        this.data = data;
    }
    public int add(T item) {
        int i = 0;
        for (; i < data.length ; i++) {
                if (item == null) {
                    return -1;
                }
                if (data[i] == null) {
                    data[i] = item;
                    break;
                }
        }
        if (data.length >1&&data[i-1] != item) {
                data = Arrays.copyOf(data,data.length+1);
                data[i] = item;
        }
        if (data.length ==1&&data[i-1] != item ) {
                data = Arrays.copyOf(data,data.length+1);
                data[i] = item;
        }
        if (data.length==0) {
            data = Arrays.copyOf(data,1);
            if (data[i] != item ) {
                data[i] = item;
            }
        }
        return i;
    }

    public T[] getItem() {
        return data;
    }
    public T get(int index) {
        if (data.length <=index) {
            return null;
        }
       return data[index] ;
    }
    public boolean delete(int index) {
        for (int i = index; i < data.length; i++) {
            if (data[i] == data[index]) {
                for (int j = index; j < data.length; j++) {
                    data[i] = data[j];
                }
            }
            data = Arrays.copyOf(data,data.length -1);
            return true;
        }
        return false;
    }
}

MAIN 

public class DataContainerMain {
    public static void main(String[] args) {
        DataContainer<Integer> dc = new DataContainer<>(new Integer[]{1,2,3});
        System.out.println(dc.add(5));
        System.out.println(dc.delete(1));
        System.out.println(Arrays.toString(dc.getItem()));

    }
}

例如，在删除包含数据的数组时 - 1,2,3 我添加 5，然后我删除索引 1 处的元素，然后它应该变成 - 1,3,5，但结果是 1， 5,3 并且总是交换最后两个元素。为什么？

public class StudentMain {

    public static void main(String[] args) throws IOException {

        StudentService ss = new StudentService();
        List<Student<Integer,String,Integer,Double,Boolean>> students = new ArrayList<>();
        for (int i = 0; i < 10_000; i++) {
            students.add(new Student<>(ss.getNumber(),ss.getNameFromFileOutSide(), ss.getAge(), ss.getRating(),ss.getOlympic()));
        }
        List<Student<Integer, String, Integer, Double, Boolean>> ageEqualOrHigherTwelve;
        ageEqualOrHigherTwelve = students;

        Iterator<Student<Integer, String, Integer, Double, Boolean>> iterator = ageEqualOrHigherTwelve.iterator();
        for (Iterator<Student<Integer, String, Integer, Double, Boolean>> it = iterator; it.hasNext(); ) {
            Student<Integer, String, Integer, Double, Boolean> student = it.next();
            if (student.getA()>=12&&student.getR()>=8) {
                ageEqualOrHigherTwelve.add(student);
            }
        }
        System.out.println(ageEqualOrHigherTwelve);

    }
    }

为什么会抛出异常？以及如何解决？

public class CalculatorWithAutoAggregationSetup1  implements ICalculator {
    ICalculator ic;
    CalculatorWithOperator cwo;
    public CalculatorWithAutoAggregationSetup1(ICalculator ic) {
        this.ic = ic;

    }
    private int counter;
    private long memory;

    public CalculatorWithAutoAggregationSetup1() {

    }


    public double divide(double a, double b) {
        counter++;
        return ic.divide(a,b);
    }

    public double multiplication(double a, double b) {
        counter++;
        return a * b;
    }

    public double plus(double a, double b) {
        counter++;
        return a + b;
    }

    public double minus(double a, double b) {
        counter++;
        return a - b;
    }

    public double square(double a, int b) {
        double square = 1;
        for (int i = 0; i < b; i++) {
            square *= a;
        }
        counter++;
        return square;
    }

    public double module(double a) {
        if (a < 0) {
            a = -(a);
        }
        counter++;
        return a;
    }

    public double root(double a) {
        double x;
        if (a<0) {
            a = -(a);
        }
        double half = a / 2;
        do {
            x = half;
            half = (x + (a / x)) / 2;
        } while ((x - half) != 0);
        counter++;
        return half;
    }
    public long getCounter() {
        return  counter;
    }

我无法理解如果我们传递一个 ICalculator 类型的对象，那么我们将不得不在 main 中创建它（据我了解），但是如果不实现其方法就无法创建接口对象。另外，您需要在没有自己数学的情况下委托方法，但据我了解，没有其他类（包括接口）我无法委托（因为它没有实现）。问题是我应该将什么传递给构造函数，或者更确切地说如何（必须传递 ICalculator），以便我可以委托方法并运行 main。

例如，第一个数字是 1。将它相乘直到溢出。对于正数，算法是明确的，对于负值则不清楚。例如数字 - 1 乘以 (- 2) 直到溢出

public class Loop5 {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        System.out.println("Введите число");
        long l = Long.parseLong(scan.next());
        Loop5 l5 = new Loop5();
        l5.longMinusValue(l);

    }

    public void longMinusValue(long l) {
        Scanner scan = new Scanner(System.in);
        System.out.println("Введите число на которое умножать");
        long l1 = Long.parseLong(scan.next());
        while (Long.MAX_VALUE > l) {
            l *= l1;
            System.out.println(l);
        }

    }
}

 import java.util.Scanner;
public class Loop1 {
    public static void main(String[] args) throws Exception {
        Loop1 l1 = new Loop1();
        l1.scannerNumber();
    }
    public void scannerNumber() {
        Scanner scan = new Scanner(System.in);
        System.out.println("Введите число: ");
        long x = 0;
        long result = 1;
        int x1 = 0;
        int x2 = 0;
        while (x1 == 0 || x1 <0) {
            try {
                if (x2 == 5) {
                    System.out.println("Слишком много попыток. Программа закрывается");
                    System.exit(0);
                }
                x = Long.parseLong(scan.nextLine());
                x1++;
                if (x<0) {
                    System.out.println("Вы ввели отрицательное число");
                    x1--;
                    x2++;
                }
            } catch (Exception e) {
                System.out.println("Повтори попытку: ");
                x2++;
            }
        }
        if (x == 0) {
            System.out.println("Result = " + result);
            return;
        }
            for (int i = 0; i < x; i++) {
                if (result < 0) {
                    System.out.println("У вас получилось переполнение " + result);
                    break;
                } else if (result > 0){
                    System.out.println("Result = " + result);
                    result *= (x - i);
                }
            }
    }
}

public class DeleteArray {

    public static void main(String[] args) {
        Random rand = new Random();
        Scanner scan = new Scanner(System.in);
        System.out.println("Введите размер массива - ");
        int x = scan.nextInt();
        int []  arr = new int[x];
        int [] arr1 = null;
        System.out.println("Введите значение a - ");
        int a = scan.nextInt();
        System.out.println("Введите значение b - ");
        int b = scan.nextInt();
        for (int i = 0;i< arr.length;i++) {
            arr[i] = rand.nextInt(10)+5;
        }
        System.out.println("" + Arrays.toString(arr));
        for (int i = 0; i < arr.length; i++) {
            if (i>=a && i<=b) {
                arr[i] = arr[i+1];
                arr[i] = 0;
            }
        }
        System.out.println("" + Arrays.toString(arr));
    }
}