C# Decimal.Round方法實例講解

Decimal.Round方法用于將值舍入到最接近的整數或指定數量的小數位數。此方法的重載列表中有4種方法,如下所示:

• Round(Decimal) 方法
• Round(Decimal,Int32)方法
• Round(Decimal, MidpointRounding) 方法
• Round(Decimal,Int32,MidpointRounding)方法

在這里,我們將討論前兩種方法。

Decimal.Round(Decimal) Method

此方法用于將十進制值舍入到最接近的整數。

用法: public static decimal Round (decimal d);
Here, it takes a decimal number to round.

返回值:此方法返回最接近d參數的整數。如果d在兩個整數之間,其中一個是偶數,另一個是奇數,則返回偶數。

異常:如果結果超出Decimal值的范圍,則此方法將引發OverflowException。

以下示例程序旨在說明Decimal.Round(Decimal)方法的用法:

范例1:

// C# program to demonstrate the // Decimal.Round(Decimal) Method using System; ??class GFG { ??????// Main Method ????public static void Main() ????{ ????????try { ??????????????// Declaring and initializing value ????????????decimal value = 184467440737095.51615M; ??????????????// getting rounded decimal ????????????// using Round() method ????????????decimal round = Decimal.Round(value); ??????????????// Display the value ????????????console.writeline("Rounded value is {0}", round); ????????} ??????????catch (OverflowException e)? ????????{ ????????????Console.WriteLine("Value must not be out of bound"); ????????????Console.Write("Exception Thrown:"); ????????????Console.Write("{0}", e.GetType(), e.Message); ????????} ????} }

輸出:

Rounded value is 184467440737096

范例2:對于OverflowException

// C# program to demonstrate the // Decimal.Round(Decimal) Method using System; ??class GFG { ??????// Main Method ????public static void Main() ????{ ??????????try?????????{ ??????????????// Declaring and initializing value ????????????decimal value = 79228162514264337593543950335.5M; ??????????????// getting rounded decimal ????????????// using Round() method ????????????decimal round = Decimal.Round(value); ??????????????// Display the value ????????????Console.WriteLine("Rounded value is {0}", round); ????????} ??????????catch (OverflowException e)? ????????{ ????????????Console.WriteLine("Value must not be out of bound"); ????????????Console.Write("Exception Thrown:"); ????????????Console.Write("{0}", e.GetType(), e.Message); ????????} ????} }

Compile-Time錯誤:

prog.cs(15,51):error CS0594:Floating-point constant is outside the range of type `decimal’

Round(Decimal, Int32) Method

此方法用于將十進制值舍入到指定的小數位數。

用法: public static decimal Round (decimal d, int decimals);

參數:
d:它是一個十進制數,將被四舍五入。
decimals:從0到28的值,指定要舍入到的小數位數。

返回值:此方法返回等于d的十進制數,四舍五入為小數位的小數位數。

異常:如果小數位數不是0到28之間的值,則此方法將引發ArgumentOutOfRangeException。

以下示例程序旨在說明Decimal.Round(Decimal,Int32)方法的用法:

范例1:

// C# program to demonstrate the // Decimal.Round(Decimal) Method using System; ??class GFG { ??????// Main Method ????public static void Main() ????{ ????????try { ??????????????// Declaring and initializing value ????????????decimal value = 7922816251426433759354.39503305M; ??????????????// getting rounded decimal ????????????// using Round() method ????????????decimal round = Decimal.Round(value, 4); ??????????????// Display the value ????????????Console.WriteLine("Rounded value is {0}", round); ????????} ??????????catch (ArgumentOutOfRangeException e)? ????????{ ????????????Console.WriteLine("decimal place is not within bound"); ????????????Console.Write("Exception Thrown:"); ????????????Console.Write("{0}", e.GetType(), e.Message); ????????} ????} }

輸出:

Rounded value is 7922816251426433759354.3950

范例2:對于ArgumentOutOfRangeException

// C# program to demonstrate the // Decimal.Round(Decimal) Method using System; ??class GFG { ??????// Main Method ????public static void Main() ????{ ????????try?????????{ ??????????????// Declaring and initializing value ????????????decimal value = 7922816251426433759354.39503305M; ??????????????// getting rounded decimal ????????????// using Round() method ????????????decimal round = Decimal.Round(value, 29); ??????????????// Display the value ????????????Console.WriteLine("Rounded value is {0}", round); ????????} ??????????catch (ArgumentOutOfRangeException e)? ????????{ ????????????Console.WriteLine("Decimal place is not within bound"); ????????????Console.Write("Exception Thrown:"); ????????????Console.Write("{0}", e.GetType(), e.Message); ????????} ????} }

輸出:

Decimal place is not within boundException Thrown:System.ArgumentOutOfRangeException

參考:

• https://docs.microsoft.com/en-us/dotnet/api/system.decimal.round?view=netframework-4.7.2