Introduction to Computer Languages

• Communication is the means to express ideas and requires a language.
• Computer language serves as an interface between humans and computers.
• It comprises words, symbols, and codes understandable by computers to write programs.

Types of Computer Languages

• Computer languages are classified into machine language, assembly language, and high-level language.

Machine Language (1GL)

• Uses binary digits (0s and 1s) grouped in sets of 8 bits (one byte).
• It directly is understood by computer hardware.
• Machine code is in binary format
• Converts all data types (text, graphics, audio) into binary format.
• Machine-dependent that does not need compilers or interpreters.
• Machine language is a first-generation language.
• Example: Character 'a' is 01100001, 'b' is 01100010
• 8 bits represent a character.
• Programs in machine language execute faster because it directly interacts with the computer.
• Code conversion is not needed if the program is written in machine language.
• Machine language is machine-dependent.
• Code in this language is in binary, which is difficult to debug.

Assembly Language (2GL)

• It is a low-level language
• Uses mnemonics (symbols and abbreviations) and op-codes (numbers).
• An "Assembler" converts it to machine language.
• MASM (Macro Assembler) is an example.
• An assembler translates assembly language code into machine language (0s and 1s).
• Uses statements instead of binary digits, so it is easily understood and developed by the programmer.
• It is easy to debug
• Needs a translator program because it's machine dependent.
• Programmers should have knowledge of mnemonics.

High-Level Language

• It overcomes the inconvenience of low-level languages
• Programs are written in English or symbols, so it is closer to human languages.
• Writing codes is easier to develop and modify.
• It needs a compiler or interpreter for execution, because it is machine-independent language.
• Third, fourth, and fifth generation languages are the three categories of high-level languages.

Third Generation Languages (3GL)

• The programmer writes English-like words to tell the computer what to do.
• Uses arithmetic operators, such as * for multiplication and + for addition.
• Examples are BASIC, PASCAL, C, FORTRAN, C++, Java, and C#.

Fourth Generation Languages (4GL)

• Uses English-like statements.
• They specify what the program should accomplish
• A 4GL is faster and takes less time to code.
• Programmers with very little programming knowledge can develop programs.
• Examples are MATLAB, Oracle Reports, or Informix.

Fifth Generation Languages (5GL)

• Natural languages are is known as the programming languages
• It has visual tools to develop a program.
• Examples include Mercury, OPS5, and Prolog.
• Natural language is very easy to use
• Natural languages are associated with expert systems and artificial intelligence.
• These systems are popular in medical and scientific fields and not widely used in business applications.

High-Level Language Advantages

• User-friendly design
• Similar to English
• Less coding time.
• Easier to maintain.
• Problem-oriented
• Can be translated into machine language to run on any computer with a translator.
• Independent of the machine.

High-Level Language Disadvantages

• Needs to be translated, wasting computer time.
• The object code may be inefficient.

Comparison of Computer Languages

Machine Language

• Uses binary digits.
• Directly understood by the computer.
• Example: Character 'A' = 01100001.

Assembly Language

• Uses mnemonics.
• Requires an assembler.
• Example: Addition uses 'Add' (Add A B).

High-Level Language

• Uses English-like language and symbols.
• Requires a compiler.
• Example: Adding 10 and 20 (int s=a + b;).

Source Code and Object Code

• Source code is written in a text editor and converted to machine language.
• Compiler or interpreter converts source code
• Object code is the program converted into machine language.

Compiler

• A compiler translates the entire source code into object code at once.
• It displays the errors for the whole program together.

Interpreter

• It translates the source code line by line before executing.
• It translates one statement at a time.
• Displays errors one line at a time.

Programming Paradigms

• High-level programming languages are classified based on their features
• There are two types of programming paradigms: Procedure-Oriented Programming (POP) and Object-Oriented Programming (OOP).

Procedure-Oriented Programming

• A model for beginners in programming
• It follows a top-down approach.
• Emphasizes methods or procedures over data values.
• Procedure programming splits the programming code into events or procedures, that contain a series of steps or instructions.
• FORTRAN, COBOL, BASIC

Procedure-Oriented Programming Principles

• Follows a top-down approach.
• Divides large programs into smaller functions or methods.
• Provides step-by-step execution instructions.

Procedure-Oriented Programming Advantages

• Reliable and tested algorithms.
• Easy to follow program flow.
• Requires less memory
• Uses functions.
• Programs can be executed on different types of processors.

Procedure-Oriented Programming Disadvantages

• Methods are shared globally.
• Debugging is required in programs.
• Emphasizes operation over data, exposing data.
• Reduces data security.
• Hard to correlate with real-world objects.

Object-Oriented Programming

• It follows a Bottom-Up approach
• It emphasizes more on data rather than functions
• Divides the program into entities, known as objects.
• Increases the ability to deal with complex software problems

Object-Oriented Programming Principles

• Data Abstraction
• Inheritance
• Polymorphism
• Encapsulation
• The four pillars of Object-Oriented Programming

Object-Oriented Programming Advantages

• Each instance has exclusive properties.
• It uses re-usability where code is written once and can be used multiple times using different objects.
• Maintaining and modifying existing code is easier
• Abstraction and Data hiding maintain data security.
• The concept of Inheritance helps avoid data redundancy by allowing code reuse.

Object-Oriented Programming Disadvantages

• Object-Oriented programs need more lines of code
• Requires more memory, and its execution may be slower.
• It requires intensive testing.
• Proper planning is necessary for designing effective programs

Difference between POP and OOP

Procedure-Oriented Programming

• Programs are divided into functions or methods.
• Uses a Top-Down approach.
• Deals with Algorithm/Procedures.
• It is less secure.
• Examples: C, Fortran

Object-Oriented Programming

• Programs are divided into objects.
• Uses the concept of Bottom-Up approach.
• Deals with data.
• It is more secure.
• Examples: C++, Java