C Language Tutorial on I/O Operations for Beginners Session 19 Video Lecture | Basics of C Language - Fundamentals of Programming - Software Development

the 19th session is on files the last
topic of the complete cessation divided
in duration file input output operations
are performed on and it is called files
binary and txt files two are two types
actually we'll be seeing one after the
other opening a file opening a file
establishes a link between the program
and the operating system without which
file about which file we are going to
access and how use the file pointer and
use the F open to create a file along
with mode and place it into the pointer
so f open is a file pointer in which I
am placing sample dot txt and say are go
for an example on this as you can see
this is to read a file create a file
pointer and a character variable F open
this says file open and this is a file
which I am going to open if it is if it
exists I will open it if it is not i
will say file not exists in there read
mode and place it in F F P equal to null
if the file is not present it will be
null if not i'll enter into the block
and i will get character by character
and LP printing it on the screen so
we'll compile the program as the file
does not exist I will be saying file not
exists if I create the file I will be
getting all those characters now we'll
see if the what happens if the file is
created so now after creating the file
when I execute this program I will be
getting the contents of that file what
all that file holds and just reading it
on the screen so the address of this
particular file is placed into the
pointer because it holds something it is
not equal to null and so I blah jump the
if block coming into the in this
indefinite loop and here file get the
character from this pointer and place it
in the CH variable it that is not equal
to the end of the character if it is
break it if not go for printing it on
the screen
dnf I'll close it and then if you say
this is a foil program to read some text
which is on the screen so this is how we
can read a particular file later on the
next thing is file opening modes as I
said R stands for reading it W stands to
write on the file and a append to close
the file say F close along with the file
pointer as you can see it's the reading
mode and I am closing that particular
file by saying FP as its argument over
here as printf function to perform at a
writing of character strings integers
floats we have to function syntax F
printf pointer variable control strings
and variables this is the syntax will go
for will take up a small example which
demonstrates a print of functional now
in this program I have an integer array
and I integer variable a file pointer I
am scanning for ten values into the
array after that after getting the
address of after getting the placing all
the address of the file pointer into FP
the pointer I'll print all those
characters file print F into the address
what FB holds later on when I read that
we'll see what happens so as of now I am
going to execute this program it asked
me to enter certain values 10 20 30 40
50 60 and 70 80 and 90 finally 100 are
the values what I've given now going
back to the previous program that is
reading that particular file and now I
am reading the same file you can see all
those inputs what I have given are
displayed on the screen so this is how
you can write something to the screen by
using f printf to a file what FB holds
and the previous program shows us to
read that particular file on the wind
just flat some similarly F scanf
function for formatter reading of
character strings integers loads we have
two functions this is a syntax so the
and gets he functions are the same
to put up the and get up the characters
from the screen and from the keyboard
this we have seen in the strings concept
to going for some more examples now we
will take up file dot C this is the one
we did just now printing up all the RS
and file with name and this if you save
file with the same pointer now I will
try to open sample dot txt in our mode
if it is there i will be printing file
not found if it is not there or else i
will come into trending all the
characters who character by character is
what I will get okay so so same thing
and doing the file character open and I
am placing the W mode in it so the Sam
dot txt is a file and I will be entering
the roll number and name therefore
asking as a user to further go for the
execution or not so now it's roll number
and name let the roll number 100 and the
other one be killin now it asks you to
me to enter whether you want to continue
or not yes to continue and against a
roll number is one not one and rename is
like some other thing again I want to go
kai yes the roll number some number and
some name now this time it's the end so
this is the program so all these files
have been saved in Sam dot txt and the
folder where it said
this is about gettin the file concepts
of first part and we could take up the
continuation in the second part as of
now
you