Introduction to Programming Languages

Introduction to Programming Language

• Computer programming defines the process of creating software using a programming language.
• Programmers write instructions step-by-step in a logical sequence to instruct computers to carry out tasks.

Programming Languages

• Programming languages serve as a vocabulary and set of grammatical rules to guide computers in completing specific tasks.
• Various programming languages exist, each with unique keywords and a distinct syntax structure.

Syntax

• Syntax refers to the spelling and grammar rules within a programming language.
• Each programming language has its own rules for word arrangement, punctuation, and structure to ensure that a computer properly interprets and executes the program's instructions.
• Text-based languages rely on sequences of characters, while visual programming languages employ symbol arrangements and connections.

Example of a Program Code (Small Basic)

• TextWindow.Writeline("enter the Temperature in fahrenheit ") prompts the user to input a temperature value in Fahrenheit.
• fahr = TextWindow.ReadNumber() reads the numeric value entered by the user for the temperature in Fahrenheit and stores it in the variable "fahr".
• celsius = (5 * (fahr - 32) / 9) calculates the equivalent value of the temperature from Fahrenheit to Celsius using the formula.
• TextWindow.WriteLine("This Temperature in celcius is " + celsius + " degrees") displays the calculated Celsius value to the user along with the units of measurement, which clarifies the output.

Levels of Programming Languages

• Computer programmers must pick the appropriate programming language to solve a particular problem based on different factors such as functionality and the desired output.
• Programming languages are categorized into five major groups: machine languages, assembly languages, third-generation languages, fourth-generation languages, and natural languages.
• Machine and assembly languages are low-level languages, whereas third-generation, fourth-generation, and natural languages are considered high-level languages.

Low-level Languages

• Low-level programming languages depend on the specific computer. Such languages are programmed directly with instructions understood by the computer.
• Machine and Assembly languages are examples of low-level programming languages.

Characteristics of 1GL

• Machine Language (1GL) is the fastest to execute as instructions are already understood by the computer.
• Programming in 1GL is difficult mainly due to mistakes being easily made in the sequence of 1s and 0s.

Assembly Language (2GL)

• Assembly language employs mnemonic codes (abbreviated English words or short codes) to convey instructions.
• These codes are simpler to understand as their meanings are more easily grasped.
• Typical codes include LDA, STO, ADD, and NOP, each with a unique meaning.

Characteristics of 2GL

• Assembly Languages are machine dependent.
• Assembly Language performs faster with proper use of hardware and is more efficient than high-level languages.
• Assemblers are required to translate Assembly code into machine language before execution.

High-level Languages

• High-level languages use variables, objects, Boolean expressions, functions, loops, arrays, threads, and locks, reflecting the underlying logic and operations.
• High-level programming languages, in contrast to low-level languages, are mostly independent of the machine, allowing programs to run on various computers after translation.
• A computer program consists of multiple instructions written in a particular programming language designed to complete a specific task.

Major High-Level Languages Used

• Major high-level programming languages such as Fortran, COBOL, RPG, BASIC, and Pascal were introduced at different historical time periods and each has a unique purpose and use case.

Language Translators

• Language translators are system software tools that convert assembly language and high-level language instructions into machine language.
• This is essential because computers only understand machine language code.

Source Code

• Source code is written by programmers in a code editor and represents instructions for the desired outcome.
• The software can't read or understand the source code directly; it needs to be translated and converted into machine code for the computer to execute.

Object code

• Object code is a processed and machine-readable form of source code, translated via a translator tool.

Assemblers and Compilers and Interpreters

• Assemblers convert assembly language into machine code.
• Compilers translate complete source code into machine code before execution, checking syntax.
• Interpreters, however, translate and execute one statement at a time, immediately after converting it. This can be slower than compiling entire programs as it must translate instructions line by line before executing.

Python Integrated Development Environment (IDE)

• IDEs are software tools that bundle the functionalities of editing, compiling, verifying, adjusting, executing, testing, and code formatting required for program development.

Types of IDEs (IDLE, PyCharm, Jupyter Notebook, Spyder, Sublime Text)

• Each IDE offers specific features and capabilities to enhance programmer efficiency and experience.

Python Programming Language

• Python is an open-source, high-level, dynamic, and interpreted language.
• Python is considered highly adaptable and versatile, with a powerful syntax and extensive pre-made tools that are easy for people to use and modify to customize programs.
• Python is also highly user-friendly, and it is useful for a wide variety of tasks.