Is an object of a class always allocated in the heap memory?

An object of a class in iOS (Objective-C or Swift) is usually allocated on the heap when created through a constructor (for example, [[MyClass alloc] init] in Objective-C or MyClass() in Swift). However, not always is a class object necessarily on the heap — for example, if a struct is used in Swift, it is allocated on the stack or in the memory where it is declared.

It is important to understand that classes are reference types, and their instances are typically stored on the heap, with variables holding references to these objects. Unlike classes, structs are value types, which are allocated on the stack or inline in memory.