Topic Smalltalk True or false If false then explain why not

Topic: Smalltalk. True or false?

If false, then explain why not (Code example would be helpful).

(a) Smalltalk is implemented from a hybrid implementation system.

(b) Smalltalk data types fall into two categories: primitive types and reference types.

(c) Variable types must be declared in Smalltalk.

(d) Smalltalk depends on garbage collection to reclaim memory occupied by no longer used objects.

(e) Smalltalk classes are built upon a single class hierarchy.

(f) Smalltalk do not support multiple inheritance. It only supports single inheritance.

Solution

The Learning Research Group at Xerox Palo Alto Research Center (PARC) developed Smalltalk as a language for the Dynabook, during the 70s and early 80s.

Smalltalk was influenced by Lisp, Simula, Ivan Sutherland\'s Sketchpad.

Smalltalk influenced the development of other object-oriented languages, such as C++, Objective C, CLOS, as well as others.

Smalltalk was the first to support the three fundamental features of object-oriented programming.

Smalltalk provides many features which are hard or impossible to implement in many other programming languages - namely closures, real reflection, dynamic late binding and a powerful integrated development environment.

(a) Smalltalk is implemented from a hybrid implementation system: False

(b) Smalltalk data types fall into two categories: primitive types and reference types: True

(c) Variable types must be declared in Smalltalk: True

The two kinds of variables commonly used in Smalltalk are instance variables and temporary variables.

(d) Smalltalk depends on garbage collection to reclaim memory occupied by no longer used objects: True

Smalltalk virtual machine is equipped with a garbage collector, a facility that reclaims the space occupied by objects that are no longer accessible from the system roots. The collector is composed of several parts, each of which can be invoked by the virtual machine using various tunable strategies, or invoked manually by the programmer.

e) Smalltalk classes are built upon a single class hierarchy:

Smalltalk\'s rich class hierarchy. Here is a simplified picture:

Object

(f) Smalltalk do not support multiple inheritance. It only supports single inheritance: True

Thank you.