为什么我的“ While Loop”不计算并打印出简单的3N + 1方程？

Question

So I had to write a simple code that would compute the 3N+1 equation; where N is an integer user types in and if it is a positive integer than N = N / 2 and if negative integer than N = N * 3 + 1.

However from what I can understand, my code doesn't work after the first while loop and hence prints nothing. What am I doing wrong? New to programming and still learning so I appreciate your help :)

Code:

import java.util.Scanner; 
public class ThreeNplusOneProgram {

    public static void main(String[] args) {

        int N; Scanner input = new Scanner(System.in); int counter; 

        System.out.println("Please Enter an integer: ");
        N = input.nextInt();

        while ( N <= 0 ) {
            System.out.println("ERROR: Please Enter an integer greater than zero: ");
            N = input.nextInt();
        }

        //So far we know that N is great than Zero

        System.out.println(N);
        counter = 1;
        while ( N != 1 ) { 

            if (N == N % 2 )
                N = N / 2; 

            else N = N * 3 + 1; 

            counter = counter + 1; 

        }

        System.out.println("There were" + counter + "terms in the sequence");
    }

}

Answer 1

这是错误的： if (N == N % 2 ) N％2返回1或0。您应该使用if (0 == N % 2 )检查奇数/偶数。

Answer 2

问题是您的if (N == N % 2) ，您可能只想检查if (N >= 0)因为您确实声明要检查if it is a positive integer 。