Programming Fundamentals Lecture 2 Overview of Computer Programming

Programming Fundamentals Lecture #2 Overview of Computer Programming Junaid Hassan Lecturer CS & IT Department UOS MBDIN junaidte 14@gmail. com

Programming/Coding • Set of rules to instruct computers to perform certain tasks is called as programming. • A language which is understandable by computers is called as programming language

Purpose of the course • To understand different programming concepts and to familiarize students with the basic structured programming skills. • Problem analysis, algorithm designing, program development and testing/debugging

Overview of Computer Programming • Set of instructions/statements we write to command computers to perform actions & make decisions is called a computer program/software • Programming language that we will use (in this course) is C/C++ • C++ is the next version or superset of C • C does not support classes & objects because C is a procedural programming language, whereas C++ is a combination of both procedural and object oriented programming capabilities

Overview of Computer Programming • A computer is a device that can perform computations & make decisions billions of times faster than humans can. • Computers process data under the control of sets of instructions called computer programs • People who write these computer programs are called as computer programmers

Machine Languages, Assembly Languages & High Level Languages • Some programming languages are directly understandable by computers but some languages require intermediate translation steps • There are hundreds of computer languages in use today • These computer programming languages can be divided into three general types: • 1) Machine Languages 2) Assembly Languages • 3) High Level Languages

Machine Languages • A language which is directly understandable by computers is called as machine language. It’s also called as natural language of computers. • Machine languages generally consits of strings of numbers (ultimately reduced to 1’s & 0’s) that instruct computers to perform their most elementary operations one at a time • Machine language programming was too slow, tedious & error prone for most programmers

Assembly Languages • Istead of using strings of numbers that computers could directly understand, programmers began using English. Like abbreviations to represent elementary operations • These abbreviations formed the basis of assembly languages • To convert assembly language code to machine language code, translator programs called assemblers were developed

Assembly Languages • Although assembly language code is clearer to humans but it’s not understandable by computers until translated to machine language code • In assembly language, programmers still need to use many instructions to accomplish even the simplest tasks • That’s why we moved to next level i. e High level languages

High Level Languages • To speed up the programming process, high level languages were developed in which single statements could be written to accomplish substantial tasks • Translator programs used to convert high level language code to machine language code are called compilers. • Advantage of high level language is that we can write instructions like every day English & with commonly used mathematical notations

Machine Languages, Assembly Languages, High Level Languages • Requirement: Add overtime pay to base pay & store the result in gross pay Machine Language Code: +1300042774 +1400593419 +1200274027

Machine Languages, Assembly Languages, High Level Languages • Requirement: Add overtime pay to base pay & store the result in gross pay Assembly Language Code: Load basepay Add overpay Store grosspay

Machine Languages, Assembly Languages, High Level Languages • Requirement: Add overtime pay to base pay & store the result in gross pay High Level Language Code: grosspay = basepay + overpay ;

Machine Languages, Assembly Languages, High Level Languages • From programmer’s point of view high level languages are preferable to machine & assembly languages • C, C++, Microsoft’s. NET languages (e. g visual basic, visual c++ & visual c#) & java are among the most widely used high level programming languages

Real World Application Areas of C/C++ • • Operating systems Development of new languages e. g python, php Computation platforms e. g matlab Graphics, games, GUI based apps Web browsers Database softwares e. g mysql and many more. . .