Understand the usage of suffixes on literals. See examples of numeric suffix syntax.
Suffix. A suffix specifies a number's type. They instruct the C# compiler that an integral literal such as 1000 be considered a certain type of number—for example, a long (1000L). We look into how you can add numeric suffixes to numbers.LongNumeric Casts
First example. Numeric suffixes, which are also called literal number suffixes, are hints to the compiler that a literal number is of a certain type. Recall that "literal" means a value hard-coded into your program.
Note: Literal suffixes on constants actually generate conv instructions. This means they work the same as runtime casts.
Letters: The letters L, D, F, U, M and UL are appended to the end of the integral literals in the declarations.
And: An "L" instructors the C# compiler that 10000 is a long type. The MSIL generated is similar to using casts such as (long)10000.
C# program that uses literal number suffixes
static void Main()
// Use long suffix.
long l1 = 10000L;
// Use double suffix.
double d1 = 123.764D;
// Use float suffix.
float f1 = 100.50F;
// Use unsigned suffix.
uint u1 = 1000U;
// Use decimal suffix.
decimal m2 = 4000.1234M;
// Use unsigned suffix and long suffix.
ulong u2 = 10002000300040005000UL;
Review. We describe the suffixes in more detail. This table indicates the meaning of the letters. We also see examples of the suffixes in the C# programming language. The code statements can be used within programs.
Suffix type: unsigned int
Example: uint x = 100U;
Suffix type: long
Example: long x = 100L;
Suffix type: unsigned long
Example: ulong x = 100UL;
Suffix type: float
Example: float x = 100F;
Suffix type: double
Example: double x = 100D;
Suffix type: decimal
Example: decimal x = 100M;
Lowercase suffixes. You can also specify lowercase suffixes, such as u, l, ul, f, d and m. But these are easier to confuse with numbers. The letter "l" is sometimes seen as the number 1.
Warning: The "l" suffix is easily confused with the digit 1—use L for clarity. The screenshot shows this warning in the IDE.
Examples of lowercase suffixes
Lowercase suffix: long x = 10000l; // Is that 100001 or 10000l?
Uppercase suffix: long x = 10000L; // It's 10000L.
Summary. Suffixes can be used on literal numbers in C# programs. This is a way to tell the C# compiler that you want the literal number to be treated as a certain type of number, similar conceptually to a cast.
Note: The specification defines how numbers are converted when used as operands, but these suffixes can force certain conversions.