C-Programming(Input-Output)

INPUT\ OUTPUT

Ø  In general, it is very necessary to read input value from keyword and to display output value on monitor. It can be achieved using I\ O statement in “C” language.

Ø  < stdio.h > Standard Input Output Header File : - It contain all functions related to input /  

                 Output operations.

Ø   Note:  In any computer language the name of function is always followed by open and close

     Parenthesis‘( )’.                               

printf( ):- It is a formatted function of < stdio.h > header file which is used to print some                 Message or valves on monitor.

Syntax1:-

printf(“hello”);àwhich is used to display any user define message on consol screen.

Ex: 1) - printf (“Hello India”);

              O/P: - Hello India

   Syntax2:-

 printf(“format specifiers” ,argument list);àwhich is used to display output values on consol screen.

Ex 2) - int X=5;

              char Y=’A’;

              float Ch=10.5;

              printf ( “%d  %f   %c” , X , Y , Ch );

              O/P        5   10.5   A

Ex 3) - printf (“Average = %f” , avg );

            O/P:    Average = 27. 8

scanf( ) :- It is a formatted function of <stdio.h> header file, which is used to scan or enter                  Some values from keyboard on moniter.

Ø  It performs two operations.

1)      Read data or accepting data from the input device keyword.

2)      Store the data in appropriate memory location.

Syntax:-

scanf(“format specifiers”, & argument list);

Ex:-

          int     X;

          char  Ch;

          float  Y;

          scanf ( “%d%f%c” , &X , &Y,&Ch);

Format specifier: - These are the special elements in “C” language used to identify type of data from keyword.

Ø  Format specifiers should be enclosed between double quotes.

Ø  Each “format specifier” starts with the character (%).

Ø  The argument list contains a list of variables.

Formatted specifiers /characters in “C”

          Data type                     Specifiers

               int                              %d, %i

              Char                             %c

              Float                            %f

              String                         %s

              Unsigned int               %u

              Long int                       %ld

              Double                        %lf

              Long double                %Lf

              Octal number               %O

              Hexadecimal (lower case latter)                %x

              Hexadecimal (upper case latter)                %X

Escape Sequence Characters (Backslash Character Constants) in C:

Ø  ASCII characters are unprintable, these characters perform special functions such as a new line, back spacing etc.

Ø  The combination of backslash and these characters are called escape sequences.

Character Constant	Meaning
\n	New line (Line break)
\b	Backspace
\t	Horizontal Tab
\f	Form feed
\a	Alert (alerts a bell)
\r	Carriage Return
\v	Vertical Tab
\?	Question Mark
\'	Single Quote
\''	Double Quote
\\	Backslash
\0	Null

Basic concept for executing programs:

• SAVE with  .c extension (in user directory)
• COMPILE = F9
• RUN = Ctrl+F9
• O/P = Alt+F5 ( to shift control to output window )  

Execution of C Program:

C program executes in following 4 (four steps).

1)      Install:- install “C” software Turbo TC1,TC2

2)      Creating a program & saved: - create “C” program and saved as “file_name.c”, an extension.

Ø  File name can be any user define name.

3)      Compiling the program: The next step is to compile the program. The code is compiled by using compiler. Compiler converts executable code to binary code i.e. object code.

4)      Linking a program to library: The object code of a program is linked with libraries that are needed for execution of a program. The linker is used to link the program with libraries. It creates a file with '*.exe' extension.

5)      Execution of program: The final executable file is then run by dos command prompt or by any other software.

Compiler: -

Ø  Compiler is a special program used to convert source code (source file) into object code.

Ø  Compiler generates object code and stored it on secondary memory (hard disk).

Ø  Object code is collection of zeros (0) and ones (1).

Linker:-

Ø  Linker is a special program used to convert assembly language instruction into machine level language instruction.

Ø  These instructions will be executed by processor with the help of operating system and gives the output\ result.

Small program of “C”:-    #include<stdio.h>

                                      void main()

Source: From Google