Programming Language & Designed Concepts 

ALGOL

Introduction:

Algol is a 2^nd generation language. It was found as a solution for the need for a machine independent programming language. It’s language specification was done using the BNF notation.

Major contributions to the modern languages:

1.        Block structure

·         Algol introduced the block structure which was so helpful in developing large scale programs by constructing small components. That was one of the major contribution to the modern programming languages.

·         This made variables to visible within their related scope. Therefore, it avoided the redeclaration of variables which was an advancement helped in the modern languages.

2.      Assignment operation

3.       Dynamic memory management

·         In Algol, the binding of the variables happened at the execution time.   

4.      Regularity of the language

·         Regular language is easier to learn. There it has the ability of replacing a bunch of statements by a single statement.

Features:

Ø  Programming structure: Blocked structure

            Avoided the re-declaration of variables. So that it improved the effective use memory.

As hierarchical structure was followed, which was introduced by ALGOL-60, the programming structure was clearer enough to understand the connection and the flow of each components with others.

There are two types of statements,

o   Declarative statements – for the variable, procedural and switch declarations

o   Imperative statements

Ø  Variable declaration:

Proper variable declaration is there with the name of the variable along with its data type.

Ø  Data types: integer, Boolean, double, real, complex and dinteger

Ø  Data structures:

Use recursive data types such as trees and list.

Dynamic arrays are used.

Ø  Control structures: Allows nested control structures such as nested for loops.

Ø  Parameter passing mechanisms:

Call by name

Pass by reference

Pass by value

Strengths and Weaknesses:

Strengths:

Facilitated with recursion. Therefore, the re writing of the codes can be avoided. It results in minimizing the wastage of computer memory.

Facilitated with conditional constructions with the use of control structures.

Weaknesses:

Lack of input-output statements