Overview of Computers and Programming Languages

An Overview of Computers and Programming Languages

• Programming languages are essential for creating software, which makes computers functional
• C++ is a versatile programming language suited for a wide range of tasks
• Programming languages have evolved over time, starting from machine language to higher-level languages like C++

The History of Computers

• Early calculating devices:

  • Abacus
  • Pascaline
  • Leibniz device
  • Jacquard's weaving looms - using punched cards for automated pattern control
  • Babbage machines, including the difference and analytic engines

• Early computer-like machines:

  • Mark I - one of the first large-scale automatic digital computers, electromechanical with thousands of components
  • ENIAC
  • UNIVAC - the first commercially produced digital computer in the US, marking the beginning of commercial computing
  • The Von Neumann architecture - describes a system where memory stores data and program instructions allowing the CPU to fetch and execute instructions sequentially

• The Von Neumann architecture consists of four main components:

  • Central Processing Unit (CPU) - performs calculations and executes instructions
  • Memory - stores data and instructions
  • Input/Output devices - allow communication with the outside world
  • Control Unit - directs the operations of the CPU and memory

• Categories of computers:

  • Mainframe computers
  • Midsize computers
  • Microcomputers (personal computers)

Elements of a Computer System

• Hardware: physical components of a computer

  • CPU - the brain of the computer, carries out arithmetic and logical operations, the most expensive hardware component
  • Main memory (RAM) - directly connected to the CPU, used to store programs and data before execution, lost upon power shutdown
  • Secondary storage - devices for permanent storage of information like hard disks, flash drives, floppy disks, CD-ROMs, and tapes
  • Input/Output devices - enable communication with the computer, input devices include keyboards, mice, and secondary storage, output devices include monitors, printers, and secondary storage

• Software: programs that perform specific tasks

  • System programs control the overall computer operation and provide services like memory management, input/output activities, and storage management
  • Application programs perform specific user tasks, examples include word processors, spreadsheets, and games

The Language of a Computer

• Analog signals: continuous wave forms representing sound

• Digital signals: sequences of 0s and 1s, with 0 representing low voltage and 1 representing high voltage

• Machine language: a computer's native language, a sequence of 0s and 1s

• Bit (Binary digit): the digit 0 or 1

• Binary code (binary number): a sequence of 0s and 1s, used to represent everything in a computer, from data to instructions

• Byte: eight bits

• Kilobyte (KB): 2^10 bytes = 1024 bytes

• ASCII (American Standard Code for Information Interchange):

  • encodes 128 characters using a sequence of 0s and 1s, for example, 'A' is encoded as 1000001 (66th character) and '3' is encoded as 0110011

• EBCDIC (Extended Binary Coded Decimal Interchange Code): used by IBM, encodes 256 characters

• Unicode: encodes 65536 characters using two bytes per character

The Evolution of Programming Languages

• Early computers were programmed in machine language: difficult to understand and write.
• Assembly language instructions were mnemonic, representing machine instructions with readable words.
• Assembler: translates assembly language programs into machine language
• High-level languages like Basic, FORTRAN, COBOL, Pascal, C, C++, C#, and Java made coding more user-friendly and efficient.
• Compiler: translates high-level language programs into machine language.

Processing a C++ Program

• C++ programs typically start with #include directives to include necessary libraries.
• using namespace std; is included to access standard functionalities from the namespace std.
• int main() is the main function where the program execution starts.
• cout is used for outputting text to the console.
• cin is used for inputting data from the user.

C++ programs are compiled and then executed, transforming code written in a high-level language into machine instructions that the computer can understand.

Explore the evolution of computers and programming languages from early calculating devices to modern programming languages like C++. This quiz covers significant milestones and innovations in the field of computing.