Question

我试图创建一个函数来给出最接近的素数到该人输入的数字，并且我没有成功。顺便说一下，我现在开始编程并且循环让我困惑，任何提示？这是以下代码：

public static void main(String[] args) {
        // Entry Mechanism
        Scanner input = new Scanner(System.in);

        // Variables
        int n1, biggestPrime;

        System.out.print("Number: ");
        n1 = input.nextInt();

        biggestPrime = biggestPrime(n1);

    }

    public static int biggestPrime(int n1) {
        int biggestPrime = 0;
        boolean isPrime = true;

        if (n1 < 0)
            return 0;

        for (int i = n1; i == 0 && isPrime == false; i--) {
            if (i % n1 == 0) {

                isPrime = false;
            }
        }
        return biggestPrime;
    }

Answer 1

我认为你不会试图找到素数的最大素数...

public static void main(String[] args) {
    // Entry Mechanism
    Scanner input = new Scanner(System.in);

    // Variables
    int n1, biggestPrime;

    System.out.print("Number: ");
    n1 = input.nextInt();

    biggestPrime = biggestPrime(n1);

}

public static int biggestPrime(int n1) {
    int biggestPrime = 0;
    int num_max = 100000;

    if (n1 < 0) {
        return 0;
    }
    else {
        for (int i = n1; i< num_max; i++) {
            for (int j = 2; j < Math.sqrt(i); j++) {
                System.out.println(j + " " + i);
                if (i==j) {
                    biggestPrime = i;
                    // break:
                    j = num_max;
                    i = num_max;
                }
                if (i % j == 0) {
                    break;
                }                      
            }
        }
    }
    return biggestPrime;
}

我无法通过此功能为我提供所有素数

1 个答案: