帮助计算然后显示百分比 [英] Help with calculating then displaying a percentage

问题描述

我一直在为我玩的游戏开发技能计算器。目前我遇到了显示百分比的正确结果的问题。我环顾四周，尝试在不同的地方发布不同的解决方案，但仍然有一些问题。



这是我到目前为止：

  private   void  CalcBtn_Click（< span class =code-keyword> object  sender，EventArgs e）
 {
  //  变量 
  int  currentXp;  //  当前技能经验 
  int 目标;  //  体验目标 
  int  remainingXp; 
  int 百分比; 
 
 currentXp =  int  .Parse（CurrentText.Text）;  //  从文本框中获取当前exp  
 goal =  INT  .Parse（GoalText.Text）;  //  获取我的目标 
 
百分比=（< span class =code-keyword> int ）（（（ double ）currentXp *  100 ）/（ double ）目标）;  //   PercentageLabel上的百分比显示为 
  //  如果我目前的经验是48500000并且目标是50000000，结果应该是97％，但它显示为9,700.00％ 
  //  如果我将结果除以100则显示为0.00％ 
  //  也尝试了（（currentXp / goal）* 100）结果显示为0.00％。 
 remainingXp =（goal-currentXp）; 
 
 RemainingLabel.Text = remainingXp.ToString（  N）; 
 PercentageLabel.Text = percentage.ToString（  p）; 
 
} 

解决方案

1.首先，您应该对用户输入进行一些验证并管理例外情况，例如可能有0值的目标==>除0会产生异常。你也应该使用 TryParse 而不是 Parse 。



2.然后你应该在百分比值的临时计算中使用 double 而不是 int ，如下所示：

  double  goal =  1 ; 
  bool  ok =  double  .TryParse（GoalText.Text.Trim（）， out 目标）; 
  if （！ok || goal <  =  0 。 0 ）
 {
  //  < span class =code-comment>通过显示错误消息或其他内容来管理错误！ 
  //   ...  
} 
  //    
  double  currentXp =  0 。 0 ; 
 ok =  double  .TryParse（CurrentText.Text.Trim（）， out  currrentXp）; 
  if （！ok || currentXp <   0 ）
 {
  //  管理上面的错误数据！ 
  //   ...  
} 
 < span class =code-comment> //    
  double  percentage =  100  .0 * currentXp / goal; 

4.最后你可以在UI中显示多少小数想要或没有小数。例如，为了显示带有2位小数的百分比，代码为：

 PercentageLabel.Text =  string 。格式（  {0：＃，0.00}，百分比）; 

嗯。

如果我尝试你的代码：

  int  currentXp;  //  当前技能经验 
  int 目标;  //  体验目标 
  int 百分比; 
 
 currentXp =  48500000 ;  //  从文本框中获取当前exp  
 goal =  50000000 ;  //  获取我的目标 
 
百分比=（< span class =code-keyword> int ）（（（ double ）currentXp *  100 ）/（ double ）目标）; 

然后百分比显示为97.



所以...我首先要检查你的文本框和GoalText中是否有正确的值 - 如果你有代码可以运行提供样本值。



使用调试器查看您的确切内容。

首先，定义百分比变量加倍。

  double 百分比; 

然后，改变你用这个计算百分比的行。

 percentage =（（（ double ）currentXp）/（双）目标）; 

问题是你将百分比存储在一个int变量中

Hi,

I have been working on a skill calculator for a game I play. currently I am having issues with getting the correct result of a percentage to display. I have looked around and tried different solutions posted at different places and am still having some issues.

here is what I have so far:

private void CalcBtn_Click(object sender, EventArgs e)
   {
       //variables
       int currentXp; //current experience in the skill
       int goal; // experience goal
       int remainXp;
       int percentage;

       currentXp = int.Parse(CurrentText.Text); //gets current exp from a text box
       goal = int.Parse(GoalText.Text); //gets what I put in as my goal

       percentage = (int)(((double)currentXp * 100) / (double)goal); // the percentage on the PercentageLabel shows up as
           //say if my current experience is 48500000 and the goal is 50000000 the result should be 97% but it shows up as 9,700.00%
           //if I divide the result by 100 it shows up as 0.00%
           //also have tried ((currentXp / goal) * 100) the result shows up as 0.00% with that as well.
       remainXp = (goal - currentXp);

       RemainingLabel.Text = remainXp.ToString("N");
       PercentageLabel.Text = percentage.ToString("p");

   }

解决方案

1.First remark you should do some validation of the user input and also to manage the exception case, like goal that could have 0 value ==> division with 0 will generate exception. Also you should use TryParse and not Parse.

2.Then you should use double and not int in temp computation of the percent value like below:

double goal = 1;
bool ok = double.TryParse(GoalText.Text.Trim(), out goal);
if(!ok || goal <= 0.0)
{
   //Manage the error by showing an error message or something!
   //...
}
//
double currentXp = 0.0;
ok = double.TryParse(CurrentText.Text.Trim(), out currrentXp);
if(!ok || currentXp < 0)
{
  //Manage the error data like above!
  //... 
}
//
double percentage = 100.0*currentXp/goal;

4.Finally you could show in the UI as many decimals you want, or no decimals. For example for showing the percent with 2 decimals here is the code:

PercentageLabel.Text = string.Format("{0:#,0.00}", percentage); 

Um.
If I try your code:

int currentXp; //current experience in the skill
int goal; // experience goal
int percentage;

currentXp = 48500000; //gets current exp from a text box
goal = 50000000; //gets what I put in as my goal

percentage = (int)(((double)currentXp * 100) / (double)goal);

Then percentage shows up as 97.

So...I'd start by checking you have the right values in your textbox and GoalText - the code works if you feed in your sample values.

Use the debugger to look at exactly what you have.

First,define your percentage variable as double.

double percentage;

Then,change then line where you are calculating the percentage with this.

percentage = (((double)currentXp) / (double)goal);

The problem was that you were storing the percentage in an int variable.

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