java – 获取范围内的素数和总素数

我是 Java的初学者.我正在编写这个程序,以显示用户提供的数字之间的所有素数.

目前的输出是：

2,3,5,7,Count: 4

但是,我希望输出如下：

“素数的数量是：”count“,它们是：”后面跟逗号分隔的所有数字

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);
    }

}

解决方法

您必须存储值,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());
    }
}