Question

我正在编写一个程序作为我学习Java的培训，可以查看用户输入的任何数字之间的偶数和奇数，这个问题是，如果我在开始时输入偶数，它将显示消息< / p>

您没有输入偶数

如果用户在开始时输入了奇数，我只希望他首先查看此消息

def prev(x):
    return x.__prev__()

class infinity_functional:
    def __init__(self):
        self.n=0
    def __next__(self):
        Next   = infinity_functional()
        Next.n = self.n + 1
        return Next
    def __prev__(self):
        Prev   = infinity_functional()
        Prev.n = self.n - 1
        return Prev
    def __repr__(self):
        return str(self.n)

enter code here

>>>x=infinity_functional()
>>>x
0
>>> next(next(next(x)))
3
>>> y=next(next(next(x)))
>>> prev(y)
2

输出为

public static void main(String[] args) { isevennumber(1, 5); } public static void isevennumber(int startwith, int endwith) { for (int i = startwith; i <= endwith; i++) { if (i % 2 == 0) { System.out.println("you have entered an even number which is " + i); } else { System.out.println("you haven't entered an even number"); } } }

对不起，有任何错误，这是我在这里的第一篇文章

Answer 1

这里的问题是，每次循环中数字都不是奇数时，它将打印您没有输入偶数的数字。

您可以尝试这样：

  public static void main(String[] args) {
    isevennumber(1, 5);
  }

  public static void isevennumber(int startwith, int endwith) {
      List<Integer> evenNumbers = new ArrayList();
      for (int i = startwith; i <= endwith; i++) {
          if (i % 2 == 0) {
              evenNumbers.add(i);
          }
      }

      if (evenNumbers.isEmpty()) {
          System.out.println("you haven't entered an even number");
          return;
      }
      System.out.println("you have entered the following even numbers " + evenNumbers);
  }

这将打印出来：

 you have entered the following even numbers [2, 4]

Answer 2

只需再添加一个author_id来检查这是否是第一次迭代：

if

Answer 3

您错过了一个步骤，这里的问题是每次循环中的数字不是奇数时，它都会打印出您没有输入偶数。

以下是适合您的正确解决方案。

    public static void isevennumber(int startwith, int endwith) {
        for (int i = startwith; i <= endwith; i++) 
        {
            if (i % 2 == 0)
            {
            System.out.println("you have entered an even number which is " + i);
            }            
            else if (i == startwith)
            {
                System.out.println("you haven't entered an even number");
            }
        }
    }

如何找到任意数字之间的偶数和奇数？

3 个答案: