File Management, CPU (2110003), Presentation

1. Cpu(2110003)
Group Project
“12.File Management”
Branch : Mech I-3
Prepared By: Jani Parth U.(150120119051)
Jerin Sibi.(150120119052)
Joshi Parth.(150120119053)
Guided By: Prof. Raxit Jani

2. INTRODUCTION
 Until Now We Have Been Using The Function Such As Scanf
And Printf To Read And Write Data. These Are Console
Oriented I/O Functions, Which Always Use The Terminal As
The Target.
 The Console Oriented I/O Pose Two Major Problem:
1. It Becomes Complex And Time Consuming To Handle Large
Volume Of Data Through Terminal.
2. The Entire Data Is Lost When Either The Program Is
Terminated.

3. A File Is A Place On The Disk Where A Group
Of Related Data Is Stored. Like Other
Language C Supports A Number Of Function
That Has The Ability To Perform Basic File
Operation, Which Include:
1. Naming A File
2. Opening A File
3. Reading Data
4. Writing Data
5. Closing A File

4. FUNCTION NAME OPERATION
 fopen()  Creates a new file for use.
 fclose()  Close a file which is open for use.
 getc()  Reads a character from file.
 putc()  Writes a character to a file.
 fprint()  Writes a set of data values to the file.
 fscanf()  Reads a set of data value from a file.
 getw()  Read an integer from the file.
HIGH LEVEL I/O
FUNCTION

5. DEFINING AND OPENING A FILE
If we want to store data in a file in the secondary memory,
we must specify certain things about the file. They include:
1) FILENAME
2) DATA STRUCTURE
3) PURPOSE
DATA STRUCTURE OF A FILE IS DEFINED AS FILE. FOLLOWING is
the general format for declaring and opening a file.
 FILE *fp;
 fp = fopen(“filename” , “mode”);

6. CLOSING A FILE
A file must be closed as soon as operation on it have
been completed. Another instance where we have to
close a file is when we want to reopen it.
The I/O library supports a function to do this for us. It
takes the following forms:
fclose(file_ pointer);

7. GETC AND PUTC FUNCTION
 The simplest file I/O functions are getc and putc. These are
the getchar and putchar functions and handle one character
at a time. The statement:
putc(c , fp1);
 Similarly, getc is used to read the character from a file that
has been opened in read mode. The statement:
c= getc(fp2) ;

8. GETW AND PUTW FUNCTION
The getw and putw are integer-oriented functions.
They are similar to the getc and putc functions
and are used to read and write integer values. The
general form are:
putw(integer ,fp);
getw(fp);

9. THE fprintf and fscanf FUNCTION
 The function fprintf and fscanf perform I/O operation that
are identical to the familiar printf and scanf functions,
except of course that they work on files. The general form:
fprintf(fp , “control strings” ,list);
 The list may include constant, variable and strings. The
general format of fscanf is:
fprintf(fp , “control strings” ,list);

10. ERROR HANDLING DURING I/O OPERATOR
It is possible an error may occur during I/O
operation on a file. They are:
1) Trying to read beyond the end- of- line mark.
2) Device overflow
3) Trying to use a file that has not been opened.
4) Trying to perform an operation on a file, when
the file is opened for another type of operation.
5) Opening a file with an invalid filename.
6) Attempting to write to a write-protected file.

11. RANDOM ACESS TO FILE
It can be achieved with the help of the functions fseek,
ftell, and rewind available in the I/O library.
Ftell takes a file pointer and return a number of type
long, that corresponds to the current position.
n = ftell(fp);
Rewind takes a file pointer and resets the position to
the start of the file.
rewind(fp);
n = ftell(fp);
fseek function is used to move the file position to a
desired location within the file.
fseek(file_ ptr , offset, position);

12. COMMAND LINE ARGUMENT
 It’s a parameter supplied to a program when the program is
invoked. For example , if we want to copy the contents of a file
X_FILE to another named Y_FILE, then:
C > PROGRAM X_ FILE Y_ FILE
 Where PROGRAM is the filename where the executable code of
the program is stored.