第三次发生其他事情后增加变量

Question

请原谅我这个愚蠢的问题，但我无法解决这个问题。 我怎样才能让事情发生every third time？

时间（左数）：

1. shipmentId = 0
2. shipmentId = 0
3. shipmentId = 1
4. shipmentId = 1
5. shipmentId = 2

6. shipmentId = 2 ....

   int occurrence = 0;
   int counter = 0;
   
    foreach (var el in elmOrderData)
           {
   
           if (el.Name == "shipmentIndex")
           {// we are entering here for every element that his name is "shipmentIndex"
               el.SetValue(shipmentId);
               secondTime++; 
           }
           if ((secondTime % 2) == 0)
           {// every third time we see "shipmentIndex" 
               secondTime = 1;
               shipmentId++;
           }
       } 
   

Answer 1

您可以使用bool，如以下示例所示。这将显示消息框1,3,5,7和9：

        bool test = false;

        for (int i = 0; i < 10; i++)
        {
            if (test)
                MessageBox.Show(i.ToString());

            test = !test;
        }

Answer 2

尝试拼凑你的笔记 - 无论是否每次都会发生。怎么样？

int occurrence = 0;
int counter = 0;

foreach(var a in list)
{
    if(some_condition)
    {
        // do something..
        occurrence++
        if(occurrence % 2 == 0)
        {
            counter++
        }
    }
}

Answer 3

为什么不只是每次增加而只是除以2？

for(var i = 0; i<20; i++)
{
    var j = i / 2; // or bit shift
    //do work on j instead of i
}