What is Difference between id and Class data types in Objective-C?

id is a generic type for all Objective-c objects.When you declare id type variable, that variable can point to any type of Objective-C object.

Ex: id name = @"Sam";

In the above example name is an id variable which is pointing to string object.

*********************************************************************************

Class is an Objective-C data type which can point to any Class Object.

Ex: Class studentClassObject = [Student class];

In the above example studentClassObject is a Class type variable which is pointing to Student class object.

Note: id type variable can even point to class object but not vice-versa