The 8- and 16-bit integral types are byte, sbyte, short, and ushort.
C# implicitly converts them to larger types as required.
This can cause a compile-time error when trying to assign the result back to a small integral type:
short x = 1, y = 1;
short z = x + y; // Compile-time error
x and y are implicitly converted to int so
that the addition can be performed.
The result is also an int, which cannot be implicitly cast back
to a short.
To make this compile, we must add an explicit cast:
short z = (short) (x + y);
The floating-point types have values that certain operations treat specially.
These special values are NaN (Not a Number), +Infinity,-Infinity, and -0.
The float and double classes have constants for NaN, +Infinity, and -Infinity, as well as other values such as MaxValue, MinValue, and Epsilon.
For example:
Console.WriteLine (double.NegativeInfinity); // -Infinity
The constants that represent special values for double and float are as follows:
| Special value | Double constant | Float constant |
|---|---|---|
| NaN | double.NaN | float.NaN |
| +infinity | double.PositiveInfinity | float.PositiveInfinity |
| -infinity | double.NegativeInfinity | float.NegativeInfinity |
| -0 | -0.0 | -0.0f |
Dividing a nonzero number by zero results in an infinite value. For example:
Console.WriteLine ( 1.0 / 0.0); // Infinity
Console.WriteLine (-1.0 / 0.0); // -Infinity
Console.WriteLine ( 1.0 / -0.0); // -Infinity
Console.WriteLine (-1.0 / -0.0); // Infinity
Dividing zero by zero, or subtracting infinity from infinity, results in a NaN. For example:
Console.WriteLine ( 0.0 / 0.0); // NaN
Console.WriteLine ((1.0 / 0.0) - (1.0 / 0.0)); // NaN
When using ==, a NaN value is never equal to another value, even another NaN value:
Console.WriteLine (0.0 / 0.0 == double.NaN); // False
To test whether a value is NaN, you must use the float.IsNaN or double.IsNaN method:
Console.WriteLine (double.IsNaN (0.0 / 0.0)); // True
When using object.Equals, however, two NaN values are equal:
Console.WriteLine (object.Equals (0.0 / 0.0, double.NaN)); // True
double is useful for scientific computations.
decimal is useful for financial computations.