C

What is C:

• C is structure oriented programming language.
• It creates the system applications, that directly interacts with hardware devices, such as drivers,kernels etc.
• C is the base of the other languages, so it is called as mother of Languages.

Facts about C:

• C was invented to create operating system called Unix.
• Most of the software have been implemented using C.
• Linux OS and RDMS MySQL are written in C.
• C is a successor of B Language which was introduced around the early 1970s.

Features of C :

• Reliability
• Portability
• Flexibility
• Interactivity
• Modularity
• Efficiency and Effectiveness

Installation of Turbo C++:

• To write C programming in friendly way we use Turbo C++.
• Turbo C++ is a Integrated Development Environment and Compiler.
• Open turbo C++ site and click on the download.

• Click on turbo C ++ to install.

• Accept the license agreement and click next.

• Click on install, to install all the setup programs.

• Installs all the features.

• After installation, click finish to launch the application.

what is stdio.h?

• Stdio.h is library that stores the many standard functions.
• These functions are use for input and output operations.
• Examples : printf() and scanf().

Variables:

• A variable is used to store data, which used in the program in any location
• Variables can contain letters, digits, characters and underscores.
• Type of the variables are:
• Char        : Used to store characters in it.
• int            : Used to hold or store integer.
• float         : Used to store the decimal value.
• double     : Used to hold long data value.
• void
• Below are Formats used for print and input the value from or to output console for desired variable.

Format String	Meaning
%d	Scan or print an integer as signed decimal number.
%f	Scan or print a floating point number.
%c	To scan or print a character.
%s	To scan or print a character string. The scanning ends at white space.

Rules to name a variable:

• Variable name must not start with a integer.
• Blank or Spaces are not allowed in variable.
• Keywords are not allowed as variable name.
• C is case sensitive upper and lower case letters are treated as different.

Strings :

• Strings are one dimensional array.
• String is group of characters combined as one word.
• String can be declared in four different ways, for example if I want store "Ravindra"
• char stringname[] = "Ravindra";
• char stringname[] = {'R','a','v','i','n','d','r','a','\0'}
• char stringname[25] = "Ravindra";
• char stringname[9] = {'R','a','v','i','n','d','r','a','\0'}

Combining two strings :

• To combine two strings we use concatenate. Syntax: strcat(string1, string2).

Loops :

• To execute a statement or group of statement multiple times we use loop.
• Loop are executed using condition.
• Type of loops:
• for
• while
• do-while
• for :
• Syntax of for loop :
                                           for(init, condition, increment)
                                         {
                                          /*code declaration*/
                                          }
• init : Executed first, used to declare loop control variable.
• Only for the first time, for loop enters into init.
• condition : Check the condition to enter into the loop or to skip the loop.
• increment: After the execution of code, it enters into increment and increments the variable.
• while:
• Syntax of while loop :
                                           while(condition)
                                           {
                                            /*code declaration*/
                                            }
• Checks the condition and enters into the loop.
• do - while :
• Syntax of do-while loop :
                                            do
                                           {
                                            /*code declaration*/
                                            }while(condition)
• do - while is name as while, but condition is checked after executing the code atleast once.
• nested loop:
• nested loop is nothing but declaring loop inside the loop.
• example :
                                         for(init, condition, increment)
                                         {
                                            for(init, condition, increment)
                                            {
                                                 /*code declaration*/
                                            }
                                         }

Decision Making :

• Sometimes we want a statement or group of statements need to be executed in specific period or condition.
• For this purpose we use decision making.
• Decision Making are mainly two types:
•  if statement
• if
• if  - else
• nested if
• switch statement
• switch
• nested switch
• if  syntax :
• if uses boolean expressions, boolean expression is true it enters into the code.
• if ( boolean expression){
  /*code declaration*/
  }
• if else syntax:
• if - else is nothing but if condition is not true it executes code in else.
• if(boolean expresssion){
  /*code declaration*/
  }
• nested if  syntax:
• declaring if inside if.
• if(boolean expression){
     /*code declaration*/
    if(boolean expression){
      /*code declaration*/
   }
  }
• switch syntax : 
• switch expression variable value is compared with each case constant expression, which ever case expression matches with expression value enters the conditions
• switch(expression){
  case constant-expression :
  /*code declaration*/
  case constant-expression :
  /*code declaration*/
  }
• nested switch syntax :
• switch(expression){
  case constant-expression:
  /code declaration*/
     switch(expression){
       /*code declaration*/
     }
  }