C - Basics

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Overview

Introduction Evolution Characteristics Structure of program Input/output statements Command line arguments Escape sequences

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Founder of C

Language

Dennis M. Ritchie

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Introduction

C language is one of the most popular computer language

structured , low level , machine dependent language

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History of c language C programming language was

developed in 1972 by Dennis Ritchie at bell laboratories of AT&T(American Telephone & Telegraph), located in U.S.A.

It was developed to be used in UNIX Operating system.

It inherits many features of previous languages such as B and BPCL.

EvolutionLanguage year Developed ByALGOL 1960 International GroupBPCL 1967 Martin RichardsB 1970 Ken ThompsonTraditional C 1972 Dennis RitchieK & R C 1978 Kernighan & Dennis

RitchieANSI C 1989 ANSI CommitteeANSI/ISO C 1990 ISO CommitteeC99 1999 Standardization

Committee

What is c language?

C is mother language of all programming language.

It is system programming language. It is procedure-oriented programming

language. It is also called mid level programming

language.

Features of C Language

There are many features of c language are given below.1) Simple2) Machine Independent or Portable3) Mid-level programming language4) structured programming language5) Rich Library6) Memory Management7) Fast Speed8) Pointers9) Recursion10) Extensible

Program structure

A sample C Program

#include<stdio.h>int main(){

--other statements // Comments after double slash}

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Running a C Program

Type a program Save it Compile the program – This will generate

an exe file (executable) Run the program (Actually the exe

created out of compilation will run and not the .c file)

In different compiler we have different option for compiling and running. We give only the concepts.

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Describe the C Program #include <stdio.h> includes the standard input

output library functions. The printf() function is defined in stdio.h .

#include <conio.h> includes the console input output library functions. The getch() function is defined in conio.h file.

void main() The main() function is the entry point of every program in c language. The void keyword specifies that it returns no value.

printf() The printf() function is used to print data on the console.

getch() The getch() function asks for a single character. Until you press any key, it blocks the screen.

The files that are specified in the include section is called as header file

These are precompiled files that has some functions defined in them

We can call those functions in our program by supplying parameters

Header file is given an extension .h C Source file is given an extension .c

Header files

This is the entry point of a program When a file is executed, the start point is

the main function From main function the flow goes as per

the programmers choice. There may or may not be other functions

written by user in a program Main function is compulsory for any C

program

Main function

Describe the C Program:-

#include <stdio.h> includes the standard input output library functions. The printf() function is defined in stdio.h .

#include <conio.h> includes the console input output library functions. The getch() function is defined in conio.h file.

void main() The main() function is the entry point of every program in c language. The void keyword specifies that it returns no value.

printf() The printf() function is used to print data on the console.

getch() The getch() function asks for a single character. Until you press any key, it blocks the screen.

First Program of C Language

#include <stdio.h>  #include <conio.h>  void main(){  printf("Hello C Language");    getch();  }  

Output of Program is,

Hello C Language

Input output function

There are two input output function of c language.

1) First is printf()2) Second is scanf()

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printf()

printf() function is used for output. It prints the given statement to the console.

Syntax of printf() is given below:printf(“format string”,arguments_list);

Format string can be %d (integer), %c (character), %s (string), %f (float) etc.

scanf()

scanf() Function: is used for input. It reads the input data from console.

scanf(“format string”,argument_list);

Input and Output

Input› scanf(“%d”,&a);› Gets an integer value from the user and

stores it under the name “a” Output

› printf(“%d”,a);› Prints the value present in variable a on

the screen

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Comments in C

Single line comment› // (double slash)› Termination of comment is by pressing

enter key Multi line comment

/*…. …….*/This can span over to multiple lines

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Constant Meaning‘a’ Audible Alert (Bell)‘b’ Back Space‘f’ Form Feed‘n’ New Line‘r’ Carriage Return‘t’ Horizontal Tab‘v’ Vertical Tab”’ Single Quote‘”‘ Double Quote‘?’ Question Mark‘\’ Backslash

‘\0’ Null

Escape Sequences

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Escape Sequences-example /* Testing the escape sequences */#include <stdio.h> int main(void){printf("Testing the escape sequences:\n");printf("-----------------------------\n"); /* 3 times audible tone */printf("The audible bell ---> \\a \a\a\a\n");printf("The backspace ---> \\b___ \bTesting\n"); /* printer must be attached...*/printf("The formfeed, printer ---> \\f \fTest\n");printf("The newline ---> \\n \n\n");printf("The carriage return ---> \\r \rTesting\r\n");printf("The horizontal tab ---> \\t \tTesting\t\n");printf("The vertical tab ---> \\v Testing\v\n");printf("The backslash ---> \\ \\Testing\\\n");printf("The single quote ---> \' \'Testing\'\'\'\n");printf("The double quote ---> \" \"Testing\"\"\n");printf("Some might not work isn't it?\n"); return 0;} 

  

Output example: Testing the escape

sequences:-----------------------------The audible bell ---> \aThe backspace ---> \

b___TestingThe formfeed, printer ---> \f

?TestThe newline ---> \nTestingriage return ---> \rThe horizontal tab ---> \t

TestingThe vertical tab ---> \v

Testing?The backslash ---> \ \

Testing\The single quote ---> '

'Testing' ' 'The double quote ---> "

"Testing""Some might not work isn't

it?Press any key to

continue . . .

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THANK YOU

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