C# - decimal Examples - Dot Net Perls

Memory. Decimal values require 16 bytes. The decimal type is a value type—it requires more memory than most other value types used commonly in C#.

Part 1 The program allocates an array of one million decimal elements. The GC.GetTotalMemory method is used to determine memory usage.

Part 2 We compute the size of each decimal in the array. This gives us the value 16 bytes.

Tip If we run a program that evaluates sizeof(decimal), we see that it returns the integer 16.

sizeof

using System; const int _count = 1000000; // One million decimals long bytes1 = GC.GetTotalMemory(true); // Part 1: allocate an array of decimal values. // ... Assign an element to make the allocation not optimized out. decimal[] array = new decimal[_count]; long bytes2 = GC.GetTotalMemory(true); array[1] = 0.1M; // Part 2: compute the memory usage of the decimal type. long difference = bytes2 - bytes1; double per = (double)difference / _count; Console.WriteLine("Program used: {0:0.0} MB", (double)difference / (1024 * 1024)); Console.WriteLine("Each decimal element required: {0:0.0} bytes", per);

Program used: 15.3 MB Each decimal element required: 16.0 bytes

Operators. Decimal is a value type. It can be manipulated with the standard numeric operators in the C# language. These include the plus, minus, multiply and divide operators.

Also You can test decimal values with the equality operator == and print decimals to the Console.

using System; decimal d = 1.0M; // Test decimal. if (d == 1.0M) { Console.WriteLine(d); } decimal y = 0.5M; // Add decimal. y += d; Console.WriteLine(y); // Subtract and multiply decimal. y -= (d * 2); Console.WriteLine(y);

1.0 1.5 -0.5

Constants. If you want to know the maximum or minimum value, access the MaxValue and MinValue constants. You can also use the One, Zero, and MinusOne constants.

const

using System; Console.WriteLine(decimal.MaxValue); Console.WriteLine(decimal.MinValue); Console.WriteLine(decimal.One); Console.WriteLine(decimal.Zero); Console.WriteLine(decimal.MinusOne);

79228162514264337593543950335 -79228162514264337593543950335 1 0 -1

Floor, Ceiling. When using decimal, you should call methods available on the decimal class instead of those in the Math class for accuracy reasons.

Info When you take the ceiling of 1.1, you get 2. When you take the floor of that same number, you receive 1.

Math.Ceiling

Math.Floor

So Ceiling is the integer above the number and the floor is the integer below the number.

using System; Console.WriteLine(decimal.Ceiling(1.1M)); Console.WriteLine(decimal.Floor(1.1M));

2 1

Arithmetic. To improve the clarity of decimal manipulations, you can use the Add, Multiply, Subtract and Divide methods. Each of these methods receives two arguments.

using System; Console.WriteLine(decimal.Add(1.1M, 1.3M)); // Add Console.WriteLine(decimal.Multiply(5.0M, 2.0M)); // Five times two Console.WriteLine(decimal.Subtract(2.0M, 1.0M)); // Two minus one Console.WriteLine(decimal.Divide(10M, 2M)); // Ten divided by two

2.4 10.00 1.0 5

Remainder. When doing important computations with money, you may want to get the remainder of a division. The remainder is the part left over after the division completes.

Here We use the Remainder() method. We show that the remainder of 2 divided by 1.5 is 0.5.

Tip This is because the 0.5 is left over after the division occurred. This is called the remainder.

using System; // Remainder of 2 divided by 1.5 is 0.5 Console.WriteLine(decimal.Remainder(2.0M, 1.5M));

0.5

Truncate. This method erases all the numbers after the decimal place. It doesn't take into consideration whether the number would be rounded up or rounded down.

Here This program shows that when we truncate 4.55, we get the number 4. Truncate returns a value of type decimal.

Info Truncate is similar to casting down, as with (int), but has different behavior on values that cannot be represented with int.

int

Cast

using System; // Truncate removes the digits after the decimal place. Console.WriteLine(decimal.Truncate(4.55M));

Negate. Negate makes positive decimals negative, and makes negative decimals positive. You could duplicate this functionality by multiplying by negative one.

using System; // Makes positive numbers negative, and negative numbers positive. Console.WriteLine(decimal.Negate(1.5M)); Console.WriteLine(decimal.Negate(-1.5M));

-1.5 1.5

Round, MidpointRounding. The decimal.Round method by default rounds down or up to the specified decimal place. You can specify the MidpointRounding to further define the required behavior.

Note The ToEven value means that when a number needs to be rounded, it is always rounded to the nearest even number.

Note 2 The AwayFromZero value means that numbers are rounded up for positive numbers and down for negative numbers.

using System; // Round to one decimal place. Console.WriteLine(decimal.Round(1.59M, 1)); // Demonstrate MidpointRounding enumeration. Console.WriteLine(decimal.Round(2.5M, 0, MidpointRounding.ToEven)); Console.WriteLine(decimal.Round(2.5M, 0, MidpointRounding.AwayFromZero));

1.6 2 3

Parse, TryParse. The decimal.Parse method will throw an exception if you feed it an incorrectly-formatted value. TryParse will handle errors by returning a false value.

Tip You should use Parse if you expect all input will be correct, and TryParse if you expect errors to be common.

int.Parse

using System; // Use Parse on arguments that are always correct. decimal value = decimal.Parse("100.01"); Console.WriteLine(value); // Use TryParse when errors are expected. decimal value2; if (decimal.TryParse("perl", out value2)) { Console.WriteLine("Not reached"); }

100.01

Convert. It is sometimes wasteful to store many decimals. You can use the "To" methods on the decimal type to convert to smaller memory representations of the number.

Warning Exceptions occur if the conversion cannot be done because the decimal value is too large to be represented in the target type.

using System; const decimal input = 5; // Convert this decimal into other compatible types. Console.WriteLine(decimal.ToByte(input)); Console.WriteLine(decimal.ToDouble(input)); Console.WriteLine(decimal.ToInt16(input)); Console.WriteLine(decimal.ToInt32(input)); Console.WriteLine(decimal.ToInt64(input)); Console.WriteLine(decimal.ToSByte(input)); Console.WriteLine(decimal.ToSingle(input)); Console.WriteLine(decimal.ToUInt16(input)); Console.WriteLine(decimal.ToUInt32(input)); Console.WriteLine(decimal.ToUInt64(input));

5 5 5 5 5 5 5 5 5 5

FromOACurrency, ToOACurrency. Decimal provides FromOACurrency and ToOACurrency. FromOACurrency receives an OA value and converts it into a decimal.

And ToOACurrency takes a decimal and converts it into an OA value. OA values are a Microsoft-specific encoding.

DateTime.FromOADate

Note You should only use these methods if you are translating Excel spreadsheets or certain Microsoft database formats.

Dot Net Perls is a collection of tested code examples. Pages are continually updated to stay current, with code correctness a top priority.

Sam Allen is passionate about computer languages. In the past, his work has been recommended by Apple and Microsoft and he has studied computers at a selective university in the United States.

This page was last updated on May 3, 2023 (rewrite).

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