If a struct cannot inherit another class or struct, why does Int32 have a ToString() method?
.net, c#, inheritance, struct
Solution
If a struct cannot inherit some class or struct,
This isn't true. All structs (and the built-in value types, like `System.Int32`, `System.Single`, etc) always implicitly inherit from `System.ValueType` (which, in turn, inherits from `System.Object`).
However, you can't make a struct that inherits from anything else.
This is clearly spelled out in the C# language spec, 4.1.1:
4.1.1 The System.ValueType type
All value types implicitly inherit from the class System.ValueType, which, in turn, inherits from class object. It is not possible for any type to derive from a value type, and value types are thus implicitly sealed (§10.1.1.2).
Then, later (4.1.3) struct is explicitly defined to be a value type:
4.1.3 Struct types
A struct type is a value type that can declare constants, fields, methods, properties, indexers, operators, instance constructors, static constructors, and nested types.
Problem
``` int a = 2; Console.WriteLine(a.ToString()); // displays 2 // definition of ToString() here - public override string ToString(); ``` Now, here are some of my understandings: - All the classes in .net get a `ToString()` method, which is inherited from the `Object` class. - A structure cannot be derived from a Class or another struct. `int` is a structure of type `Int32`, which gets a couple of `ToString()` [With Parameters] methods from the Interfaces which it implements. - There is also a `ToString()` [without params] function in struct `Int32` According to http://msdn.microsoft.com/en-us/library/system.int32.tostring.aspx, struct Int32 overrides ValueType.ToString() method If a struct cannot inherit some class or struct, can you please explain how this `ToString()` method is available for `Int32`?