Input / Output Functions (I/O) - Predefined

Tutorials

Cpp

Topic

What are Input / Output Functions in C++?
Types of Predefined I/O functions in C++

Explanation

Character based Input / Output (I/O) functions supported by C++ are based on its predecessor C. All the functions supported by the C++ Standard Function Library are termed as ANSI C I/O system. To use these predefined I/O functions in a C++ program, the header file <cstdio.h> should be included.

Most of these functions set a built in global integer variable "errno" when an error is encountered. This variable stores the information about the error occured, so that it can be reffered by C++ programs.

Following table lists few character based predefined Input / Output(I/O) functions of C++ Standard function Library.

Name	Description
scanf	Reads the input from standard input.
fscanf	Reads from the named input stream.
sscanf	Reads the characters in the specified format.
printf	Prints the output to the standard output.
sprintf	Prints the output to the standard output.
fprintf	Outputs the formatted output of argument values to the stream.
vprintf	Formats and prints a series of characters and values to standard output.
vfprintf	Formats and writes a series of characters, values to the output stream.
vsprintf	Formats and stores a series of characters and values in the buffer target-string.
fopen	Opens a file, then returns the stream associated.
freopen	Associates an existing stream with a different file.
getc	Returns the next character from input stream.
fgetc	Gets the next character from the input stream, increments the file position indicator.
fgets	Reads upto num-1 characters from the stream, places them to an array.
ungetc	Returns the character specified by the low order byte.
putc	Writes a character to the stream,at current position then advances the file position indicator.
fputc	Writes a character to the stream,at current position then advances the file position indicator.
puts	Writes a string to the standard output device.
clearerr	Resets the error flag of a stream.
feof	Checks the file position indicator to find the end of stream.
ferror	Checks for the file error for the stream.
perror	Prints an error message to stderr.
fflush	Used to write the content of the output buffer to the file.
fgetpos	Stores the current value of file position indicator.
fsetpos	Moves the file position of the stream to a new location within the file.
fseek	Sets the file-position indicator for the stream pointed to by stream.
fread	Read the specified number of objects to place them in a array.
ftell	Returns the current file position indicator for the current stream.
fwrite	Writes from an array by counting the objects with the size to a stream.
rewind	Moves the file position indicator to begining of the stream.
remove	Used to erase the specified file.
tmpfile	Opens a temporary file, then returns the pointer to the stream.
tmpnam	Generates a unique filename then stores in an array.
setbuf	Specifies the buffer used by the stream.

Input / Output (I/O) Functions in C++