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javac#objecttypesprimitive

What is the difference between the terms non-primitive type and object type?

When I read about Java, I generally see variables described as either primitive type or object type.

When I read about C#, I generally see variables described as either primitive type or non-primitive type?

What is the difference between the terms object type and non-primitive type?

Solution

  • Part of this confusion may be in that, in C#, (mostly) everything inherits from Object. To refer to an Object type in the same way, would refer to every type in the language, and essentially be useless.

    In C#, the primitive types are Boolean, Byte, Char, Double, Int16, Int32, Int64, IntPtr, SByte, Single, UInt16, UInt32, UInt64, UIntPtr. These types still inherit from object, though they are treated differently by the language. There are a few types that don't inherit from object, but they are not what you would consider primitives (ie Interfaces). The list of C# primitives can be acquired with this code, taken from here:

    var primitives = typeof(int).Assembly.GetTypes().Where(type => type.IsPrimitive).ToArray();

    A more appropriate dichotomy, if you wanted such a thing, would be value types versus reference types. When you begin considering that difference, then you can include things such as Enum types, and other values type, like structs.