Introduction to Programming Concepts

Introduction to Programming

• Programming involves creating or developing software, which is also known as a program.
• A program consists of a set of instructions written in a programming language that instructs a computer to do a task.

Why Create Programs?

• Humans are inventors, creating programs solve problems using a programming approach.
• Creating programs makes life easier.

More Reasons to be a Developer

• In 2023, 8 of the top 10 richest people in the world are IT entrepreneurs/developers.
• The other 2 are investors, involved in insurance, stocks, and luxury goods.
• Several of the richest people are on the list, among them are:
  • Elon Musk has $218.6 Billion
  • Jeff Bezos has $155.9 Billion
  • Bill Gates has $115.2 Billion

Program Execution

• Programs are permanently kept in secondary memory like a hard disk.
• Instructions are encoded as binary numbers which is also known as machine code.
• When executed, the program is copied into main memory, and the CPU executes the instructions.
• Programs may read data from secondary memory and input devices.
• Flow control (if-then-else, loops) dictates the order of instruction execution.
• Program data is stored in main memory.
• Results are written to output devices or secondary memory.

Programming Language Basics

• Programs must be written in a language that a computer can use.
• There are hundreds of programming languages that make the programming process easier.
• All programs must be converted into a language that the computer can understand.

Machine Language

• Machine language is a computer's native language, varying among computer types.
• It consists of primitive instructions written in binary code, for example, for adding two numbers: 1101101010011010.
• Programming in it is tedious and makes the code difficult to read and modify.

Assembly Language

• Assembly language uses a "mnemonic" short descriptive word to represent machine-language instructions.
• It's still tedious to write in assembly language.
• An example of Assembly code mnemonic add means to add numbers.
  • To add numbers 2 and 3 and get the result, your instruction in assembly code would look like: add 2, 3, result.
• Assemblers translate assembly languages into machine code

High-Level Language

• High-level languages use English-like statements, are easy to learn and program.
• They were introduced in the 1950s and are platform-independent, enabling a program written in a high-level language to run on different types of machines.
• Instructions are called statements.
• High-level languages need to be translated into machine code using an interpreter or compiler.
• For example to calculate the area of a circle you could use area = 5 * 5 * 3.1415

Interpreter

• The interpreter reads statements one by one, translates them to machine code, and executes immediately.

Compiler

• A compiler translates the entire statement into a machine-language file for execution

Interpreter vs Compiler

• Interpreters take single instructions as inputs while compilers take entire programs.
• Interpreters don't use intermediate object code while Compilers generate intermediate Object Code.
• Condition control statements execute slower in interpreters but faster in compilers.
• Interpreters require less memory but compilers need more.
• Errors are displayed for every instruction interpreted, while they are displayed after the entire program is checked in compilers.

Programming Languages

• There are many programming Languages like:
  • Cobol
  • Python
  • Fortran
  • Visual Basic
  • Pascal
  • Ada
  • Java
  • Basic
  • C programming
  • C#
  • JS
  • PHP
  • C++

Programming Language Characteristics

• Programming languages are characterized by their programming paradigm. (Pattern/Standard/Methodology)
• A programming paradigm provides the programmer's view of code execution.
• A language isn't limited to a single paradigm.
• Java supports elements of procedural and object-oriented programming, used in a concurrent, event-driven way.
• Programming paradigms grow and evolve, as new generations of hardware and software have opportunities and challenges.

Programming Paradigms

• Different types of Programming Paradigms:
  • Procedural Programming
  • Structured Programming
  • Object-Oriented Programming
  • Other Paradigms

Procedural Programming

• Procedural programming specifies a list of operations that the program must complete to reach the desired state.
• Each program has a starting state, a list of operations, and an ending point.
• Procedures are small sections of code that perform a particular function.
• This is easier for programmers to understand and maintain program structure

Structured Programming

• Provides management tools for larger programs by breaking them into smaller modules, subroutines, and subprograms.
• It's associated with a "top-down" design approach.
• The top-down approach contains minimal details about the parts of a program.
• Design iterations add increasing detail to the components until the design is complete.

Object Oriented Programming

• Object-oriented programming Specifies both data structures and the types of applicable operations.
• A program becomes a collection of cooperating objects instead of a list of instructions.
• It can store state information and inter act with objects; each object generally has a distinct, limited role.
• Since objects/groups can be divided among teams and developed in parallel, it's manageable for larger projects.

Other Paradigms

• Concurrent Programming Languages - These support multiple threads of program execution.
• Functional Programming Languages – define subroutines/programs as mathematical functions for math problem solving.
• Event-Driven Programming Languages - The program uses an event loop to check for events.
• Events cause the execution of trigger functions, determining program flow.
• The program flow is determined by user actions here.

Choosing a Language

• Some programming languages are decades old, and are made for specific purposes: by:
  • Building on strengths of previous languages
  • Providing new and unique tools
  • Providing more programming languages

Which Language to Choose? Continued...

• There's no "best" language because They each have strengths and weaknesses.
• Programmers know that one language might work in some places, and another might be more appropriate somewhere else.
• Java is a programming language that is used now, and it is easy to pick up other languages once familiar.

Program Conversion

• There are multiple levels of language that will be converted into machine code for execution.
  • Languages like JAVA or C will be at the top as High Level Language
  • Then Assembly language
  • Then Machine Language
  • Then Hardware

Program Development

• Editor - For creating a file with your program.
• IDE (Integrated Development Environment) - Combines editor, compiler, debugger, and other tools into a single application.
• There various IDE's out there:
  • Eclipse
  • Apache NetBeans IDE
  • Visual Studio
  • Android Studio

Program Development Key Terms

• Source Program / Source Code - Program in a high-level language.
• Syntax - Rules of grammar and vocabulary of a language.
• Semantics – the meaning of something written in the language.
• A program can be syntactically correct but semantically incorrect.
• Quality programs are both syntactically and semantically correct.

Program errors

• During programming, errors can occur, so students must learn to pinpoint and fix them through practice.
• These fall these into three categories.

Types of Program Errors

• Compile-time error - This is when the compiler cannot resolve an issue in source code (syntax error).
• Runtime error - This is when execution of a statement or function results in an error condition.
• Logic error - A logic error occurs when a program compiles successfully but behaves unexpectedly, such as incorrect solutions.

Summary

• There are opportunities presented in learning to program.
• We can talk to a computer when it only understands machine code.
• Recognize the types of programming patterns and their details.
• Programming development environment is software to create programs and a common vocabulary.
• Programming Errors will occur, and the types of error need to be identified.