C# types

1. A C# program is a collection of types: classes, structs, enums, interfaces, delegates, etc.
2. Pre-defined data types: int, byte, char, string, object, etc. Similar to other language, we can create our own types. There are no global variables nor global functions.
3. Type contains:

• Data member:
• Fields, constants, arrays
• Events
• Function member:
• Methods, operators, constructors, destructors
• Properties, indexers

4. There are 3 categories of types:

• Value: directly contains data on the stack, cannot be null
• Pointer (only in unsafe mode)
• Reference: contains references to objects, may be null. (keeps a reference on the stack, but allocates the real memory on the heap)