The variables that are based on value types directly contain values. The characteristics of value-type variables that are supported in C# programming language are as follows: All value-type variables derive implicitly from the System.ValueType class You cannot derive any new type from a value type Value types have an implicit default constructor that initializes the default value of that type The value type consists of two main categories: Structs – Summarizes small groups of related variables. Enumerations – Consists of a set of named constants.
Keywords are those words that are reserved to be used for a specific task. These words cannot be used as identifiers. You cannot use a keyword to define the name of a variable or method. Keywords are used in programs to use the features of object-oriented programming. For example, the abstract keyword is used to implement abstraction and the inherits keyword is used to implement inheritance by deriving subclasses in C# and Visual Basic, respectively. The new keyword is universally used in C# and Visual Basic to implement encapsulation by creating objects.