Introduction handout
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C is a widely used programming language developed in the 1970s. It allows direct manipulation of bits, bytes and addresses for low-level programming tasks like operating systems development. The C standard library contains many pre-existing functions that programmers can use rather than reinventing functionality, making development more efficient. Key advantages of C include portability across hardware, support for various data types, and flexibility between high-level and low-level programming.
Introduction handout
- 1. 2/12/2010 t y Keep your notebook with you. C Write important point and questions that comes in your mind Solve Mind band exercise. Programming C Rewind when not clear Language Ask Questions by call or SMS or by mail By: Keep Watching Keep Learning Yogendra Pal yogendra@learnbywatch.com THIS IS INTRODUCTION Dedicated to My mother and Father 2 Computer Computer… • Electronic Device • Two very important for a programmer • Store, Manipulate and Transmit data. – Numeric • Data can be – Character – Numeric • Scientific and Engineering Applications – Character (Name, Address etc.) – Numeric – Graphics data (Charts, Photographs, Videos) • Business applications – Sound (Music, Speech etc.) – Numeric and Character 3 4 Memory Memory… • Every information is stored in binary code. • Bit is the smallest unit of information storage. • Binary code is the sequence of 0s and 1s. • Bit consists a single binary digit (0 or 1). • 0 and 1 are called bits. • We can interpreted 0 and 1 as: • 0 represents OFF and 1 represents ON. – 0 : False : Off • 8 bits makes 1 byte. – 1 : True : On 7 6 5 4 3 2 1 0 • Character takes one byte to store. 5 6 1
- 2. 2/12/2010 Memory… Machine needs instructions • o 1 bit consists 0 or 1. • • 8 bits makes a byte. 210 (1024) byte make a Kilobyte or KB. I • 210 (1024) Kilobyte make a Megabyte or MB. • 210 (1024) Megabyte make a Gigabyte or GB. • 210 (1024) Gigabyte make a Terabyte or TB. Bit < Byte < KB < MB < GB < TB ć 7 8 Programming Language Machine Language • Machine Language • Strings of numbers giving machine specific • Assembly Language instructions. • High-Level Language • Also known as Machine code. Example: +1300042774 +1400593419 +1200274027 9 10 Machine Language… Assembly Language • Very Few programs are written in machine • English-like abbreviations representing language because:- elementary computer operations. – It is very difficult to work with machine language. • Simpler than machine language. – Program written for one type of computer will not Example: run on other type of computer (Each type of LOAD BASEPAY ADD OVERPAY computer has it’s own instruction set). STORE GROSSPAY • Translate in machine code before execute. • Translation is done by assembler. 11 12 2
- 3. 2/12/2010 High-level Languages High level languages… • Codes similar to everyday English (Easy to • The program written in high level language is understand). known as source code or source program. • Use mathematical notations. • The compiled source code results in machine- • Example language. – grossPay = basePay + overTimePay • Machine language code is also known as • Translate in machine code before execute. object code or object program. • Translation is done by compiler or interpreter. 13 14 Compiler vs. Interpreter Program • Interpreter reads the source code one line at a • Using programming language we create time convert it into machine code. instructions or set of instructions. • Compiler reads the entire program and • This set of instructions is also knows as converts it into machine code. computer program or software program or • machine code is a code that the computer can just program. run directly. • Example programs or softwares: • machine code also known as object code or – Word processing program binary code. – Computer Games or video games 15 16 History of C C: A Middle Level Language • Evolved by Dennis Ritchie in 1970 at Bell • Best elements of high level language and Telephone Laboratories from two previous control and flexibility of assembly language. programming languages, BCPL and B. • C allows the direct manipulation of bits, bytes • Used to develop UNIX. and addresses. • Used to write modern operating systems. • C has several built in data types. • Hardware independent (portable). • Permits type conversion. • Standard created in 1989, updated in 1999. • No run time error checking. BCPL B C Martin Richards Ken Thompson Dennis Ritchie • Well suited for system-level programming. 17 18 3
- 4. 2/12/2010 The C Standard Library C Standard Library… • C programs consist of pieces/modules called • Avoid re-inventing the wheel functions. – If a premade function exists, generally best to use it – A programmer can create his own functions. rather than write your own • Advantage: the programmer knows exactly how it works – Library functions carefully written, efficient, and • Disadvantage: time consuming portable – Programmers will often use the C library functions. • Use these as building blocks 19 20 Other High-level Languages Structured Programming • Other high-level languages • Disciplined approach to writing programs. – FORTRAN • Functions are the building blocks of programs. • Used for scientific and engineering applications • Allow you to code separate tasks in a program, – COBOL make your program modular. • Used to manipulate large amounts of data – Pascal • Clear, easy to test and debug and easy to • Intended for academic use modify. • C is a structured programming language. 21 22 Library and Linking Program Development • Library : Collection of functions. • Edit : Program is created in the editor and stored on disk. • Linker : Combines the called function object • Preprocess: Preprocess program processes the code code with the code you written. • Compile : Compiler creates object code and stores it on disk. • Link : Linker links the object code with the libraries. • Load : Loader loads program in memory. • Execute : CPU takes each insruction and executes it. 23 24 4
- 5. 2/12/2010 Form of C program Mind Bend • The main() function must present in program. • Write 4 different data types. • Keywords can not used as a variable name or a • What is meant by a computer program? function name. • Differentiate bit & byte? • Case sensitive language. • What is a machine language? How it is different from High level language? – else ELSE • What are the advantages of high level • It may have many functions. language? Give some examples of high level language. 25 26 To get complete benefit solve all the quiz on Mind Bend www.learnbywatch.com • Differentiate Compiler and Interpreter. For any problem in this tutorial mail me at yogendra@learnbywatch.com • What is source program? with the subject “C” • What is object program? For Other information mail at • Who develop the C language and where? info@learnbywatch.com • Can we use uppercase in C program? Keep Watching Keep Learning • Computer is an __________ device. NEXT IS C BASICS • Binary code is the sequence of _ & _. 27 5