File Management functions

A File can be used to store a large volume of persistent data. Like many other languages ‘C’ provides following file management functions,

1. Creation of a file
2. Opening a file
3. Reading a file
4. Writing to a file
5. Closing a file

Creating and Opening Files

The fopen( ) function to create a new file or to open an existing file. This call will initialize an object of the type FILE, which contains all the information necessary to control the stream. The prototype of this function call is as follows –

FILE  *fopen( const  char  * filename, const  char  * mode );

Following are the list of functions which are used for reading a file:

Functions	Syntax	Description
fscanf( )	int fscanf (FILE *stream, const char *format,....);	It is used for reading the formatted data from the stream.
fgets( )	char *fgets(char *str, int size, FILE *stream);	It stands for file get string. It is used for getting the string from a stream.
fgetc( )	int fgetc (FILE *stream);	It will return the next character from the stream from the end of the file or an error.
fread( )	int fread(void *str, size_t size, size_t num, FILE *stream);	It is used for reading data from a file.

Following are the list of functions which are used for writing a file:

Functions	Syntax	Description
fprintf()	int fprintf (FILE *stream, const char * format,...);	It is used for writing the formatted output of the stream.
fputs()	int fputs(const char *str, FILE *stream);	It is used for writing a line to a file.
fputc()	int fputc(int c, FILE *stream);	It is opposite to fgetc() and is used for writing a character to the stream.
fwrite()	int fwrite(const void *str, size_t size, size_t count, file *stream);	It is used for writing data to a file.

Following are the functions which are used for detecting the errors:

Functions	Syntax	Description
clearerr()	void clearerr(FILE *stream);	It is used for clearing the end-of-file and error indicators for the stream.
perror()	void perror(char *msg);	It stands for the print error.

Closing a file :

After every successful file operation, always close a file.

For closing a file, fclose function is used.

Ex:

filePointer= fopen(“fileName.txt”, “w”);

---------- Some file Operations -------

fclose(filePointer)