1. Classes are reference types and structs are value types.
Since classes are reference type, a class variable can be assigned null.But we cannot assign null to
a struct variable, since structs are value type.
2. When you instantiate a class, it will be allocated on the heap.When you instantiate a struct, it gets created on the stack.
3. You will always be dealing with reference to an object ( instance ) of a class. But you will not be dealing with references to an instance of a struct ( but dealing directly with them ).
4. When passing a class to a method, it is passed by reference. When passing a struct to a method, it's passed by value instead of as a reference.
5. You cannot have instance Field initializers in structs.But classes can have
example:
class SClass
{
int aVar =10; // no syntax error.
public void aFun( )
{
// statements
}
}
struct SStruct
{
int aVar = 10; // syntax error.
public void aFun( )
{
// statements
}
}
6. Classes can have explicit parameterless constructors. But structs cannot have
7. Classes must be instantiated using the new operator. But structs can be
8. Classes support inheritance.But there is no inheritance for structs.
9. Since struct does not support inheritance, access modifier of a member of a struct cannot be
protected or protected internal.
10. A class is permitted to declare a destructor.But a struct is not
11. Classes are used for complex and large set data. structs are simple to use
12. Structure couldn't be Null like a class
13. Structure couldn't have a destructor such as class
14. Structure can't be abstract, a class can.
15. You can't use sizeof with classes but you can with structures
16. A structure must have always the default parameter less constructor be defined as public but a class might have one, so you can't define a private parameter less constructor
struct Me
{
private Me() // compile-time error
{
}
}
class Me
{
private Me() // runs Ok{
}