Structured Programming
Structured programming is a programming approach that emphasizes writing clear, organized, and logical code by dividing a program into smaller, manageable sections or functions. It uses three main control structures—sequence, selection, and iteration—to control the flow of the program instead of using unstructured jumps like goto statements. This method promotes top-down design, making programs easier to read, debug, test, and maintain. It is commonly used in languages such as C, Pascal, and Python, and forms the foundation of modern programming practices.
1. INTRODUCTION TO STRUCTURED PROGRAMMING
1.1. Development of Programming Language
FIRST GENERATION OF PROGRAMMING LANGUAGE
The first generation of programming language, or 1GL, is machine language. Machine language
is a set of instructions and data that a computer's central processing unit can execute directly.
Machine language statements are written in binary code, and each statement corresponds to one
machine action.
SECOND GENERATION PROGRAMMING LANGUAGE
The second generation programming language, or 2GL, is assembly language. Assembly
language is the human-readable notation for the machine language used to control specific
computer operations. An assembly language programmer writes instructions using symbolic
instruction codes that are meaningful abbreviations or mnemonics. An assembler is a program
that translates assembly language into machine language.
THIRD GENERATION PROGRAMMING LANGUAGE
The third generation of programming language, 3GL, or procedural language uses a series of
English-like words, that are closer to human language, to write instructions.
High-level programming languages make complex programming simpler and easier to read,
write and maintain. Programs written in a high-level programming language must be translated
into machine language by a compiler or interpreter.
PASCAL, FORTRAN, BASIC, COBOL, C and C++ are examples of third generation
programming languages.
FOURTH GENERATION PROGRAMMING LANGUAGE
The fourth generation programming language or non-procedural language, often abbreviated as
4GL, enables users to access data in a database.
A very high-level programming language is often referred to as goal-oriented programming
language because it is usually limited to a very specific application and it might use syntax that is
never used in other programming languages.
SQL, NOMAD and FOCUS are examples of fourth generation programming languages.
FIFTH GENERATION PROGRAMMING LANGUAGE
The fifth generation programming language or visual programming language is also known as
natural language. Provides a visual or graphical interface, called a visual programming
environment, for creating source codes. Fifth generation programming allows people to interact
with computers without needing any specialized knowledge. People can talk to computers and
the voice recognition systems can convert spoken sounds into written words.
Prolog and Mercury are the best known fifth-generation languages.
EXT : OPEN PROGRAMMING LANGUAGE
The Open Programming Language (OPL) is an embedded programming language found in
portable devices that run the Symbian Operating System. For example mobile telephones and
PDAs. OPL is an interpreted language that is analogous to BASIC.
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