C#中的Float / Double类型输入验证
发布时间：2020-12-15 23:48:07 所属栏目：百科 来源：网络整理
导读：这实际上是我写的第一个程序(上周一开始学习);我是个新手. 我的问题是,当程序提示用户输入fahreinheit或celsius条目(期待一个数字)时,如何防止用户输入无效字符时抛出异常？因此,例如,当用户输入“asfasd”时,程序会抛出异常. 在发布之前我在网站上做了很多
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这实际上是我写的第一个程序(上周一开始学习);我是个新手.
我的问题是,当程序提示用户输入fahreinheit或celsius条目(期待一个数字)时,如何防止用户输入无效字符时抛出异常？因此,例如,当用户输入“asfasd”时,程序会抛出异常. 在发布之前我在网站上做了很多搜索,我成功地找到了其他输入验证问题,然而,他们都是关于C和C的,因为我是一个新手,我很难理解那些语言以及它们与C#的关系.谢谢.请看代码： using System;
namespace Converter
{
class Program
{
static void Main()
{
float? FahrenheitInput = null;
double? CelsiusInput = null;
float? KilogramInput = null;
float? PoundsInput = null;
int UserChoice = 0;
do
{
Console.WriteLine("What would you like to convert? Enter the corresponding number.n1. Fahrenheit to Celsius");
Console.WriteLine("2. Celsius to Fahrenheitn3. Pounds to Kilogramsn4. Kilograms to poundsn5. Exit program");
UserChoice = int.Parse(Console.ReadLine());
switch (UserChoice)
{
case 1:
Console.WriteLine("Enter the temperature in Fahreinheit,number only:");
FahrenheitInput = float.Parse(Console.ReadLine());
Console.Clear();
Console.WriteLine(FahrenheitInput + " degrees fahrenheit in Celsius is " + Program.FahrenheitToCelsius(FahrenheitInput) + "nn");
break;
case 2:
Console.WriteLine("Enter the temperature in Celsius,number only:");
CelsiusInput = double.Parse(Console.ReadLine());
Console.Clear();
Console.WriteLine(CelsiusInput + " degrees Celius in fahrenheit is " + Program.CelsiusToFahrenheit(CelsiusInput) + "nn");
break;
case 5:
break;
default:
Console.WriteLine("This is not a valid entry. Please enter 1,2,3,4,or 5.");
break;
}
} while (UserChoice != 5);
}
public static float? FahrenheitToCelsius(float? INPUT)
{
return (INPUT - 32) * 5 / 9;
}
public static double? CelsiusToFahrenheit(double? INPUT)
{
return INPUT * 1.8 + 32;
}
}
} 解决方法
您可以将其放在Try-Catch块中,也可以使用while循环来验证用户输入.
下面是带有while循环的代码,用于验证用户输入. class Program
{
static void Main(string[] args)
{
double FahrenheitInput = 0;
double CelsiusInput = 0;
double KilogramInput = 0;
double PoundsInput = 0;
int UserChoice = 0;
do
{
Console.WriteLine("What would you like to convert? Enter the corresponding number.n1. Fahrenheit to Celsius");
Console.WriteLine("2. Celsius to Fahrenheitn3. Pounds to Kilogramsn4. Kilograms to poundsn5. Exit program");
UserChoice = int.Parse(Console.ReadLine());
switch (UserChoice)
{
case 1:
Console.WriteLine("Enter the temperature in Fahreinheit,number only:");
while (!double.TryParse(Console.ReadLine(),out FahrenheitInput))
{
Console.WriteLine("Invalid format,please input again!");
};
Console.Clear();
Console.WriteLine(FahrenheitInput + " degrees fahrenheit in Celsius is " + Program.FahrenheitToCelsius(FahrenheitInput) + "nn");
break;
case 2:
Console.WriteLine("Enter the temperature in Celsius,out CelsiusInput))
{
Console.WriteLine("Invalid format,please input again!");
};
Console.Clear();
Console.WriteLine(CelsiusInput + " degrees Celius in fahrenheit is " + Program.CelsiusToFahrenheit(CelsiusInput) + "nn");
break;
case 5:
break;
default:
Console.WriteLine("This is not a valid entry. Please enter 1,or 5.");
break;
}
} while (UserChoice != 5);
}
public static double FahrenheitToCelsius(double INPUT)
{
return (INPUT - 32) * 5 / 9;
}
public static double CelsiusToFahrenheit(double INPUT)
{
return INPUT * 1.8 + 32;
}
}
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