What is the purpose of the struct in C#?

In C#, a struct is a value type data structure used to store a set of related data. It is used to create custom data types, similar to classes, but with some key differences.

1. Value type: a struct is a value type, with its instances stored in the stack rather than the heap. This means that when a struct is declared as a local variable, it will be directly stored in the call stack without allocating additional memory space. In contrast, a class is a reference type, with its instances stored in the heap and variables only storing references (pointers to the instances).
2. Performance advantage: Since struct is a value type, its storage and access speed is usually faster than classes. This is advantageous for storing small amounts of data or in performance-sensitive applications.
3. – Inheritance and polymorphism are not supported: structs cannot inherit from other structures or classes, and cannot be used as base classes. They also cannot use virtual and abstract modifiers.
4. Default constructor: A struct will automatically provide a default parameterless constructor if one is not explicitly defined, which will initialize all fields with default values.
5. Stack Allocation: When instantiating a struct using the new keyword, it gets allocated on the heap and returns a reference to that instance. However, it is possible to directly allocate and initialize an instance on the stack using the struct’s default constructor.

In summary, the role of struct in C# is to provide an efficient value type data structure for storing and manipulating a set of related data. It has certain advantages in specific scenarios such as storing and passing small data structures and in high-performance applications. However, in other cases, using classes may be more suitable.