Math.Floor Method (Double)
Returns the largest integer less than or equal to the specified double-precision floating-point number.
Assemblies: mscorlib (in mscorlib.dll)
System.Runtime.Extensions (in System.Runtime.Extensions.dll)
The behavior of this method follows IEEE Standard 754, section 4. This kind of rounding is sometimes called rounding toward negative infinity. In other words, if d is positive, any fractional component is truncated. If d is negative, the presence of any fractional component causes it to be rounded to the smaller integer. The operation of this method differs from the Ceiling method, which supports rounding toward positive infinity.