java获取范围内的素数和总素数

Question

我是Java的初学者。我写这个程序是为了显示用户提供的数字之间的所有素数

电流输出为：

2, 3, 5, 7, Count: 4

但是，我希望输出是这样的：

"The number of prime is: "+count+", and they are: " followed by all the numbers separated by comma

package com.example.test;

import java.util.Scanner;

public class PrimeTest {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out
                .println("Enter the number till which the prime numbers are to be calculated: ");
        int input = scanner.nextInt();

        int count = 0;

        // loop through the numbers one by one
        for (int i = 2; i < input; i++) {

            boolean isPrimeNumber = true;

            // check to see if the number is prime
            for (int j = 2; j < i; j++) {
                if (i % j == 0) {
                    isPrimeNumber = false;
                    break; // exit the inner for loop
                }
            }

            // print the number if prime
            if (isPrimeNumber) {
                count++;
                System.out.print(i + ", ");

            }

        }
        System.out.println("Count: " + count);
    }

}

Answer 1

将素数存储在一个数组中，并在循环外的末端显示它们

Answer 2

获取范围内的素数和总素数

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class ListPrimeNumbers {

    /**
     * @param args
     * @throws IOException 
     * @throws NumberFormatException 
     */
    public static void main(String[] args) throws NumberFormatException, IOException {

        int count=0;
        int limit;

        System.out.println("Enter the Limit:");

        InputStreamReader read = new InputStreamReader(System.in);
        BufferedReader in = new BufferedReader(read);

        limit = Integer.parseInt(in.readLine());

        System.out.println("Prime numbers From 1 to " + limit);

        //loop from 1 to limit
        for(int i=1; i < limit; i++) {

            boolean isPrime = true;

            //check to see if the number is prime
            for(int j=2; j < i ; j++) {

                if(i % j == 0) {
                    isPrime = false;
                    break;
                }
            }
            // print the number
            if(isPrime) {
                System.out.print(i + " ");
                count++;
            }
        }
        System.out.println("\nTotal Prime Number in given range: "+count);
    }

}

输出：

输入限制：

十

从1到10的素数

12357

给定范围内的总质数：5

Answer 3

必须存储这些值，例如：

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;


public class PrimeTest {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("Enter the number till which the prime numbers are to be calculated: ");
        int input = scanner.nextInt();
        List<Integer> primes = new ArrayList<>();

        // loop through the numbers one by one
        for (int i = 2; i < input; i++) {
            boolean isPrimeNumber = true;

            // check to see if the number is prime
            for (int j = 2; j < i; j++) {
                if (i % j == 0) {
                    isPrimeNumber = false;
                    break; // exit the inner for loop
                }
            }

            // print the number if prime
            if (isPrimeNumber) {
                primes.add(i);
            }
        }
        System.out.println("The number of prime is: " + primes.size() + ", and they are: " + primes.toString());
    }
}

Answer 4

将生成的素数保存到列表中，最后生成输出。例如：

System.out.println("The number of prime is: " + list.size());
foreach(int prime : list)
    System.out.print(prime + ", ");