问题

When I run my program and put 0.00000001 to root nothing happens but when I put the whole number it runs fine. I'm expecting the method to work for decimals too. I also need a Message box with the message "Please enter a positive number when a negative answer is put in.

{
    int number = Convert.ToInt32（txtNumber.Text）;
    double root = 1;
    int i = 0;
    //用于计算平方根的巴比伦方法
    while（true）
    {
        i = i + 1;
        root =（number / root + root）/ 2;
        if（i == number + 1）{break; }
    }

    lbResult.Text = root.ToString（）;
}```

<details>
<summary>英文:</summary>

When I run my program and put 0.00000001 to root nothing happens but when I put the whole number it runs fine. I&#39;m expecting the method to work for decimals too. I also need a Message box with the message &quot;Please enter a positive number when a negative answer is put in.

private void btnCalc_Click(object sender, EventArgs e)
{
int number = Convert.ToInt32(txtNumber.Text);
double root = 1;
int i = 0;
//The Babylonian Method for Computing Square Roots
while (true)
{
i = i + 1;
root = (number / root + root) / 2;
if (i == number + 1) { break; }
}

        lbResult.Text = root.ToString();

}

        

</details>


# 答案1
**得分**: 2

我建议使用巴比伦算法：

```csharp
private void btnCalc_Click(object sender, EventArgs e)
{
    double number = Convert.ToDouble(txtNumber.Text);
    if (number <= 0)
    {
        MessageBox.Show("请输入一个正数");
        return;
    }
    double x = number;
    double y = 1;
    double tol = 0.000001;
    while (x - y > tol)
    {
        x = (x + y) / 2;
        y = number / x;
    }
    lbResult.Text = x.ToString();
}

private void btnCalc_Click(object sender, EventArgs e)
        {
            double number = Convert.ToDouble(txtNumber.Text);
            if(number <= 0)
            {
                MessageBox.Show("Please enter a positive number");
                return;
            }
            double x = number;
            double y = 1;
            double tol = 0.000001;
            while (x - y > tol)
            {
                x = (x + y) / 2;
                y = number / x;
            }
            lbResult.Text = x.ToString();
        }

答案2

得分: 1

"I'm expecting the method to work for decimals too."

然后也许不要使用输入来做这个，而是解析为除了 int 之外的其他类型：

decimal number = Convert.ToDecimal(txtNumber.Text);

你需要一个 decimal：

int number = Convert.ToInt32(txtNumber.Text);

var number = Convert.ToDecimal(txtNumber.Text);