Introduction to Computers and Programming

Introduction to Computers and Programming

• Programmers write programs to instruct a computer.
• A computer without a program cannot function.

Computer Systems: Hardware and Software

• There are five main hardware categories: CPU, Main Memory, Secondary Storage, Input Devices, and Output Devices.
• The CPU consists of a control unit and an arithmetic and logic unit.
• The control unit retrieves and decodes program instructions and coordinates other computer components.
• The arithmetic and logic unit is optimized for high-speed numeric calculations and true/false decisions.
• Main memory is volatile, meaning it is erased when the program terminates or the computer is turned off.
• Main memory is also known as RAM.
• Main memory is organized into bits and bytes. A bit is the smallest unit of memory and can be either 0 or 1, while a byte is 8 consecutive bits.
• Each byte in memory has a unique address.
• Secondary storage is non-volatile, retaining data even when the program isn't running or the computer is off.
• Secondary storage comes in various forms: magnetic, solid-state, optical, and flash drives.
• Input devices send information to the computer, such as keyboards, mice, touchscreens, scanners, digital cameras, and microphones.
• Disk drives, CD drives, and DVD drives can also be considered input devices.
• Software categories include system software and application software.
• System software manages the computer hardware and other programs. Examples include operating systems, utility programs, and software development tools.
• Application software provides services to the user, such as word processing, games, and programs to solve specific problems.

Programs and Programming Languages

• Programs are sets of instructions that computers follow to perform tasks.
• Algorithms are well-defined steps that are the basis of programs.
• Computers only execute instructions in machine language, which is written in binary numbers.
• Programmers use programming languages instead of machine language to write programs.
• Programming languages are categorized as low-level or high-level.
• Low-level languages communicate directly with computer hardware and are often written in binary code.
• High-level languages are closer to human language.
• C++, BASIC, FORTRAN, Java, Visual Basic, COBOL, C#, JavaScript, C, and Python are some well-known programming languages.
• To create an executable file from a high-level program:
  • create a source file with a text editor.
  • run the preprocessor to convert source file directives to source code program statements.
  • run the compiler to convert the source program into machine instructions.
  • run the linker to connect hardware-specific code to machine instructions.
• Integrated Development Environments (IDEs) combine tools for writing, compiling, and debugging programs into a single software application.
• Examples of IDEs include Microsoft Visual C++, Turbo C++ Explorer, CodeWarrior, and others.

What is a Program Made of?

• Common elements in programming languages include:
  • Key Words
  • Programmer-Defined Identifiers
  • Operators
  • Punctuation
  • Syntax
• Key Words, also known as reserved words, have special meanings in C++ and cannot be used for other purposes.
• Programmer-defined identifiers are names created by the programmer for variables, functions, etc.
• Operators perform operations on data and can be arithmetic, assignment, or other types.
• Punctuation characters mark the end of a statement or separate items in a list.
• Syntax is the set of rules for using keywords, operators, symbols, and punctuation in a program.
• A variable is a named storage location in the computer’s memory for holding data.
• To create a variable, you must write a variable definition, also called a variable declaration.
• Variable definitions specify the type of data a variable can hold and its name.

Input, Processing, and Output

• Programs typically perform three steps:
  • gathering input data from the keyboard or files on disk drives.
  • processing the input data.
  • displaying the output to the screen or writing it to a file.

The Programming Process

• The programming process includes:
  • Define problem.
  • Design the program.
  • Write the program in a programming language.
  • Test and Debug the program.
  • Document and Maintain the program.

Procedural and Object-Oriented Programming

• Procedural programming focuses on the program's processes, with procedures/functions written to manipulate data.
• Object-Oriented programming centers on objects that combine data and methods to manipulate that data. Objects interact by exchanging messages.

Introduction to C++

• C++ programs consist of several parts, including:

  • Header files: Contain pre-written code to provide functionality.
  • The main() function: The starting point for program execution.
  • Statements: Instructions that the computer follows.
  • Comments: Explanations of the program's code.

• C++ programs typically include the following components:

  • Header files: Provide prewritten code.
  • Namespaces: Organize program elements.
  • The main() function: The program's entry point.
  • Variables: Store data.
  • Input/output: Functions for interacting with the user.
  • Operators: Perform operations on data.
  • Statements: Instructions to be executed by the computer.
  • Comments: Explanation of the code.
  • Block of code: A sequence of statements enclosed in curly braces.

• Basic syntax rules in C++ include:

  • Case sensitivity: Uppercase and lowercase letters are treated differently.
  • Punctuation: Semicolons mark the end of statements.
  • Keywords: Predefined words with specific meanings.
  • Identifiers: Names given to variables, functions, and other program elements.
  • Operators: Symbols used to perform operations.
  • Whitespace: Blank spaces and line breaks are ignored.

• Basic operations in C++ include:

  • Input: Obtaining data from the user.
  • Output: Displaying data to the user.
  • Assignment: Storing values in variables.
  • Arithmetic operations: Performing calculations on numbers.
  • Comparison operators: Comparing values.
  • Logical operators: Combining logical expressions.

• Examples of how to write basic C++ programs using simple statements, expressions, and operators to perform calculations and output results.

• C++ programs are typically structured into functions.

• Functions are blocks of code that perform a specific task.

• The main() function is the entry point for program execution.

• C++ supports data types like int for integers, double for floating-point numbers, char for characters, and string for strings.

Programming Tips in C++

• Focus on good programming practices from the beginning:
  • Follow proper syntax and style.
  • Choose meaningful variable names.
  • Use comments to explain code.
  • Test and debug code thoroughly.
  • Consider using an Integrated Development Environment (IDE).
• Key points to remember in C++ programming:
  • Understand basic syntax rules.
  • Use data types effectively.
  • Work with functions and the main() function.
  • Use input and output statements to interact with the user.
  • Perform calculations and comparisons using operators.
  • Write clear and readable code.
  • Test and debug your code thoroughly.