File in C File in C ProgrammingProgramming

Contents Data Files File Types File opening and closing Data File Type Specifications Data File Creating Data File Processing

Data File A data file is a computer file which stores data for use by a

computer application or system.

It generally does not refer to files that contain instructions or

code to be executed (typically called program files), or to files

which define the operation or structure of an application or

system (which include configuration files, directory files, etc.);

but to files that specifically contain information used as input,

and/or written as output by some other software program.

Types of Data FilesData Files of two Kinds

Stream-oriented Data File or Standard Data File

System-oriented Data File or Low-level Data File

Stream-oriented Data Files

Text File

Unformated Data File

Data Files ProcessingData Files Opening

FILE *ptvar; To create buffer area for file Handling

ptvar = fopen(filename, filetype);

To open a file and return a pointer that is assigned to ptvar.

Data Files Closing

fclose(ptvar); To close the file using the pointer ptvar.

Data File type Specifications

“r” To open the file as read mode.

“w” To open the file as write mode.

“a” To open the file as append mode.

“r+” To open the file as read + write mode.

“w+” To open the file as write + read mode.

“a+” To open the file as append + read mode.

Data File Processing Functionsfopen() To open a file and return a pointer.

fclose() To close a file with the given pointer.

getchar() To take input from the standard input device.

putchar() To give output to the standard output device.

getc() To take input from the file.

putc() To give output to the file.

fprintf() To send output a data item to the file.

fscanf() To take input a data item from the file.

Data File Creating Program 1//program for creating a file test01.dat#include <stdio.h>#include <conio.h>#include <ctype.h>void main(){

FILE *fpt;char c;fpt=fopen("c:\test01.dat","w");clrscr();printf("\n\tEnter text: ");do

putc(toupper(c=getchar()),fpt);while(c!='\n');fclose(fpt);getch();

}

To create a buffer area

To open a file and return a pointer

To write a character to the file

To close the file

Data File Reading Program 2

//program for reading and displaying from a file test01.dat

#include <stdio.h>

#include <conio.h>

#include <ctype.h>

void main()

{

FILE *fpt;

char c;

clrscr();

if((fpt=fopen("test01.dat","r"))==NULL)

printf("\n\nError");

else

{

printf("\n\tText from the file\n: ");

do

putchar(c=getc(fpt));

while(c!='\n');

}

fclose(fpt);

getch();

}

To create a buffer area

To open a file

To read a character from a file and display

To close a file