C# Data Type Keywords Reference Sheet
Submitted by oscar on Sun, 01/24/2010 - 16:57
The following table shows common data type keywords.
| Keyword | .NET Framework Type | Description | Value Range | Variable Declaration Example |
| bool | System.Boolean | Boolean type; a bool value is either true or false. | true or false | bool val1 = true; bool val2 = false; |
| byte | System.Byte | 8-bit unsigned integral type | 0 to 255 | byte val1 = 12; |
| char | System.Char | 16-bit unicode character | 0 to 65535 | char c = ‘a’; char c = 255; |
| decimal | System.Decimal | 128-bit fixed-point decimal type with 28 significant digits | -7.9e28 to 7.9e28 | decimal val = 1.23M; |
| double | System.Double | 64-bit double-precision floating point type | -1.79e308 to 1.79e308 |
double val1 = 1.23; double val2 = 4.56D; |
| float | System.Single | 32-bit single-precision floating point type | -3.40e38 to 3.40e38 | float val = 1.23F; |
| int | System.Int32 | 32-bit signed integral type | -2,147,483,648 to 2,147,483,647 | int val = 12; |
| long | System.Int64 | 64-bit signed integral type | -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 |
long val1 = 12; long val2 = 34L; |
| sbyte | System.SByte | 8-bit signed integral type | -128 to 127 | sbyte val = 12; |
| short | System.Int16 | 16-bit signed integral type | -32,768 to 32767 | short val = 12; |
| string | System.String | Immutable string of 16-bit Unicode characters | All valid string characters | string val = "Hello world." |
| uint | System.UInt32 | 32-bit unsigned integral type | 0 to 4,294,967,296 | uint val1 = 12; uint val2 = 34U; |
| ulong | System.UInt64 | 64-bit unsigned integral type | 0 to 18,446,744,073,709,551,615 | ulong val1 = 12; ulong val4 = 78UL; |
| ushort | System.UInt16 | 16-bit unsigned integral type | 0 to 65535 | ushort val1 = 12; |
Be aware of the following special cases when initializing data types:
- When initializing a char, use single quotes surrounding the letter.
- When initializing a string, use double quotes surrounding the text.
- When initializing a value that includes the decimal point,
- For a decimal type, follow the number with the letter M.
- For a float type, follow the number with the letter F.
- Under other special circumstances, you might be required to include letter values following the numeric values for other data types.
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