Programming in C

478 Appendix B The Standard C Library

int puts (buffer)

Writes the characters contained in bufferto stdoutuntil a null character is encoun-

tered. A newline character is automatically written as the last character (unlike the

fputsfunction). On error,EOFis returned.

int remove (fileName)

Removes the specified file. A nonzero value is returned on failure.

int rename (fileName1, fileName2)

Renames the file fileName1to fileName2,returning a nonzero result on failure.

void rewind (filePtr)

Resets the indicated file back to the beginning.

int scanf (format, arg1, arg2, ..., argn)

Reads items from stdinaccording to the format specified by the string format(see

Chapter 16).The arguments that follow formatmust all be pointers.The number of

items successfully read and assigned (excluding %nassignments) is returned by the

function.The value EOFis returned if an end of file is encountered before any items

have been converted.

FILE *tmpfile (void)

Creates and opens a temporary binary file in write update mode ("r+b"); it returns

NULLif an error occurs.The temporary file is automatically removed when the pro-

gram terminates. (A function called tmpnamis also available for creating unique, tem-

porary file names.)

int ungetc (c, filePtr)

Effectively “puts back” a character to the indicated file.The character is not actually

written to the file but is placed in a buffer associated with the file.The next call to

getcreturns this character.The ungetcfunction can only be called to “put back” one

character to a file at a time; that is, a read operation must be performed on the file

before another call to ungetccan be made.The function returns cif the character is

successfully “put back”; otherwise, it returns the value EOF.

In-Memory Format Conversion Functions

The functions sprintfand sscanfare provided for performing data conversion in

memory.These functions are analogous to the fprintfand fscanffunctions, except a

character string replaces the FILEpointer as the first argument.You should include the

header file <stdio.h>in your program when using these routines.

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