java - 打印前N个质数

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Calculating and printing the nth prime number
                                
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该语句是：编写一个程序，该程序读取整数N并打印前N个素数。

public static void main(String[] args)
{
    Scanner scan = new Scanner(System.in);

    int N = scan.nextInt();
    int x = 2;

    for(int i = 0; i <= N; i++)
    {
        int count = 0;

        for(int j = 1; j <= x; j++)
            if(x%j == 0)
                count++;

        if(count == 2)
            System.out.print(x + " ");

        x++;
    }
}

当我运行这段代码时，并没有给出确切的N个数字。例如，对于N = 1和2，它打印前2个素数，对于N = 3和4，它打印前3个素数，对于N = 5和6，它打印前4个素数，依此类推。此代码有什么问题？

最佳答案

我认为您的程序中有许多缺陷需要修复，因此我决定编写一个更简单，优雅的程序。

Scanner scan = new Scanner(System.in);
int N = Integer.parseInt( scan.nextLine());
int count = 0;
int num = 2;
while(count != N) { // while count!= number of prime numbers entered keep searching..
    boolean prime = true;// to determine whether the number is prime or not
    for (int i = 2; i <= Math.sqrt(num); i++) { //efficiency matters
        if (num % i == 0) {
            prime = false; // if number divides any other number its not a prime so set prime to false and break the loop.
            break;
        }

    }
    if (prime) {
        count++;
        System.out.println(num);
    }
    num++; see if next number is prime or not.
}

关于java - 打印前N个质数，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/33725505/