What Does Sizeof Operator Mean?
Sizeof operator, in C#, is an operator used to determine the size (in bytes) of an unmanaged type that is not a reference type.
While developing applications that involve dynamic memory allocation, it is very common to find the memory allocated to a type. It is very unsafe to assume the size of a type and use the hard-coded value in the application, as this may break the application when ported to different systems. The sizeof operator is used in such cases to find the size of a compound data type like a struct. However, it can only be used to compute the byte size of value types and not for reference types due to the virtualized type layout system of the .NET framework.
The sizeof operator helps in memory allocation for data structures that are passed out of managed application to unmanaged code like Interop, custom serialization, etc. Increment and decrement operators, which operate on pointers, use the sizeof operator internally to increment or decrement the address contained in a pointer variable by a value equal to the number of bytes occupied by the type of pointer. The sizeof operator helps improve code readability.