while()&中是否有区别? ... while()循环吗? [英] Is there a difference in while() & do...while() loops?
问题描述
好吧，愚蠢的问题，我完成了软件设计课程，其中的口头禅是..while至少执行一次，而while()可能永远不会执行.
我写了一个应用程序，该应用程序在一个早上不工作后因某种原因才开始工作，它突然出现在生活中(！)，它在经过一会儿循环后发现昨天是或"的三个循环之后才开始工作. ed
Okay silly question I have done the Software design courses where the mantra is do..while executes at least once, while() may never execute.
I have written an App thats has just started working for some reason after a morning of not working it has sprung into life(!) it started to work yesterday after fiddling with a while loop that had three bools in that were ''or''ed
if (Tolerance3 == false)
{
DUT3 = Convert.ToInt16(txtDUTVal3.Text);
Gold3 = Convert.ToInt16(txtGold3.Text);
if (DUT3 < Gold3)
{
IncreaseDUT3();
}
if (DUT3 > Gold3)
{
DecreaseDUT3();
}
if ((!(DUT3 < GoldTol3Min)&&!(DUT3>GoldTol3Max)))
{
Tolerance3 = true;
MessageBox.Show("Tolerance 3");
}
if (Tolerance3 == true)
{
MessageBox.Show("Tolerance3 = true");
FileName = INIPath + "\\MagZero.txt";
if (!File.Exists(FileName))
{
StreamWriter sw = new StreamWriter(FileName);
sw.WriteLine("Mag Zero "
+ dt.ToString("M_d_yyyy_HH:mm")
+ "\n\t Sensor3: "
+ txtDUTVal3.Text
+ " PWM Value: "
+ txtPWMvalue3.Text
+ "\n");
sw.Close();
}
else
{
StreamWriter sw = File.AppendText(FileName);
sw.WriteLine("\n"
+ "\n\t Sensor3: "
+ txtDUTVal3.Text
+ " PWM Value: "
+ txtPWMvalue3.Text
+ "\n");
sw.Close();
}
}
}
现在没有执行，它已经开始了.为什么为什么?我无法发布无法可靠工作的代码.可以看到该值发生了变化，但并非总是会评估该值，而此工作的前两个版本就像一个咒语一样，我想知道C#是否遇到中断，然后跳转到服务例程，然后返回，则看到while的条件之一遇到了叶子. ，或获取另一个中断并触发while循环条件的其余部分
Glenn
wasn''t executing now it has started. WHY?, WHY? I can''t ship code that won''t reliably work. The value can be seen to change but not always evaluated while the first two versions of this work like a charm I am wondering if C# gets an interrupt jumps to the service routine and then returns sees one of the coditions of the while met a leaves it, or gets another interrupt and ignors the rest of the while loop conditions
Glenn
推荐答案
除非条件为true，否则不会运行while()循环.do...while()循环将始终至少运行一次.
以下将至少运行一次
Awhile()loop will not run unless the codition is true. Ado...while()loop will always run at least once.
The following will run at least one time
bool x = true;
while (x)
{
// do something that could possibly change x to false
}
由于条件为假，因此以下while循环将不会执行.
The following while loop will not execute because the condition is false.
bool x = false;
while (x)
{
// do something that could possibly change x to false
}
以下内容将始终至少执行一次
The following will always execute at least once
bool x = true;
do
{
// do something that may change the value of x
} while (x);
那是两者之间的主要区别.
您还可以在这些循环内使用break或continue来使代码短路，以退出循环或开始新的迭代.
最后，您可以执行以下操作:
That''s the primary difference between the two.
You can also use break or continue inside those loops to short-circuit code to either exit the loop or start a new iteration.
Lastly, you can do this:
while (true)
{
}
...或这个:
...or this:
do
{
} while (true);
它创建一个循环，直到遇到break语句为止.
It creates a loop that keeps going until it encounters a break statment.
示例:
int x = 6;
而(x< = 5)
{
Console.WriteLine("while" + x);
x ++;
}
x = 6;
做{
Console.WriteLine("Do While" + x);
x ++;
} while(x< = 5);
查看此代码的输出，然后您将了解其中的区别.
Example :
int x = 6;
while (x <= 5)
{
Console.WriteLine("while "+x);
x++;
}
x = 6;
do{
Console.WriteLine("Do While "+x);
x++;
}while(x<=5);
see the output of this code, then you will understand the difference.
首先，更改此内容:
First, change this:
if ((!(DUT3 < GoldTol3Min)&&!(DUT3>GoldTol3Max)))
{
Tolerance3 = true;
MessageBox.Show("Tolerance 3");
}
对此:
to this:
if (DUT3 >= GoldTol3Min && DUT3 <= GoldTol3Max)
{
Tolerance3 = true;
MessageBox.Show("Tolerance 3");
}
其次，我们无法告诉您为什么您的代码只是开始独立运行.我们对其余的代码一无所知.
Second, there''s no wy we can tell you why your code just starts to work on its own. We don''t knwo ANYTHING about the rest of the code.
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