• In C programming, file is a place on disk where a group of related data is stored.
• When the program is terminated, the entire data is lost in C programming.
• If you want to keep large volume of data, it is time consuming to enter the entire data.
• But, if file is created, this information can be accessed using few commands.
• There are large numbers of functions to handle file I/O in C language.
• High level file I/O functions can be categorized as: Text file & Binary file.

File Operations:

• Creating a new file.
• Opening an existing file.
• Reading from and writing information to a file.
• Closing a file.

Modes in which file can opened:

The allowed modes for fopen are as follows:

r - open for reading

w - open for writing (file need not exist)

a - open for appending (file need not exist)

r+ - open for reading and writing, start at beginning

w+ - open for reading and writing (overwrite file)

a+ - open for reading and writing (append if file exists)

Functions to read and write files are:

fputc ():

• This function is used to put a character type data into the opened file using the fopen() function, pointed by a file pointer.
• The characters to be put into a file as well as the file pointer are to be passed as the parameters to this function.

Syntax: fputc(<char type="" data="">, <file pointer="" identifier="">);

Example: fputc(c, fp);

getc ():

• This function is used to get a character from the file pointed by the corresponding file pointer passed to the function.
• It is exactly opposite the fputc function.

Syntax: getc(file pointer identifier>);

Example: getc(fp);

fprintf ():

• This function is used to store the different data types in the file as the fputc() function is used to store the character in the file.
• This can be used to store integer, float, string etc types of data into the file opened.

Syntax: fprintf(<file pointer="" identifier="">, “<format specifiers="">”, <variable names="">);

Example: fprintf(fp, “%d”, x);

fscanf ():

• This function is used to read the different types of data as the getc() function is used to read a character from the file.
• This function can be used to read an integer, float string etc types of dara into the file opened.

Syntax:

fscanf(<file pointer="" variable="">, “<format specifiers="">”, <address of="" the="" variables="" in="" which="" the="" data="" is="" to="" be="" read="">);

Example:

fscanf(fp, “%d”, &x);