7/28/2019 8.Lect-9 IO

1/14

DATA INPUT AND OUTPUT

Mohit Arora

Lecturer , LIECA

LPU

7/28/2019 8.Lect-9 IO

2/14

INPUT/OUTPUT IN C

C has no built-in statements for input or

output.

A library of functions is supplied to perform

these operations. The I/O library functions

are listed the header file .

You do not need to memorize them, just be

familiar with them.

7/28/2019 8.Lect-9 IO

3/14

STREAMS

All input and output is performed with

streams.

A "stream" is a sequence of characters

organized into lines.

Each line consists of zero or more characters

and ends with the "newline" character.

7/28/2019 8.Lect-9 IO

4/14

TYPES OF STREAMS IN C

Standard input stream is called "stdin" and is

normally connected to the keyboard

Standard output stream is called "stdout" and

is normally connected to the display screen.

Standard error stream is called "stderr" and

is also normally connected to the screen

7/28/2019 8.Lect-9 IO

5/14

I/O FUNCTIONS IN C

There are six i/o functions in C are:

1. getchar()

2. putchar() 3. printf()

4.scanf()

5.gets() 6.puts()

7/28/2019 8.Lect-9 IO

6/14

GETCHAR()

getchar();

Single character can be entered in computer

using C.

Example: Char c;

.

C=getchar();

7/28/2019 8.Lect-9 IO

7/14

PUTCHAR()

putchar();

It is used to display single char.

Examplechar c=H;

putchar(c);

7/28/2019 8.Lect-9 IO

8/14

SCANF

scanf ( ) ; This function provides for formatted input from

the keyboard. The syntax is:scanf( format , &var1, &var2, ) ;

The format is a listing of the data types of thevariables to be input and the & in front of eachvariable name tells the system WHERE to storethe value that is input. It provides the addressfor the variable.

Example:float a; int b;scanf(%f%d, &a, &b

7/28/2019 8.Lect-9 IO

9/14

FORMAT OF DATA

Format Conversion Specifiers:d -- displays a decimal (base 10) integer

l -- used with other specifies to indicate a "long"

e -- displays a floating point value in exponentialnotation

f -- displays a floating point value

g -- displays a number in either "e" or "f" format

c -- displays a single characters -- displays a string of characters

7/28/2019 8.Lect-9 IO

10/14

STRINGS

When you enter string data the compiler

automatically add \0 in the end of string;

Char name[22];

gets(name);

ROHIT

But actual value stored in computer isROHIT\0

7/28/2019 8.Lect-9 IO

11/14

PRINTF

This function provides for formatted output tothe screen. The syntax is:

printf( format, var1, var2, ) ;

The format includes a listing of the datatypes of the variables to be output and,optionally, some text and controlcharacter(s).

Example:float a ; int b ;

scanf( %f%d, &a, &b ) ;

printf( You entered %f and %d \n, a, b );

7/28/2019 8.Lect-9 IO

12/14

GETS AND PUTS

To input a string to computer

gets(name);

Puts is used to display string data on screen puts(name);

7/28/2019 8.Lect-9 IO

13/14

ANY QUESTIONS

7/28/2019 8.Lect-9 IO

14/14

THANK YOU