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Created page with "<strong>SCANF</strong> ==SYNOPSIS== #include <stdio.h> int scanf(char * fmt, ...) int vscanf(char *, va_list ap); ==DESCRIPTION== <strong>Scanf</strong>() performs fo..."
<strong>SCANF</strong>
==SYNOPSIS==
#include <stdio.h>
int scanf(char * fmt, ...)
int vscanf(char *, va_list ap);
==DESCRIPTION==
<strong>Scanf</strong>() performs formatted input ("de-editing") from
the stdin stream. Similar functions are available for
streams in general, and for strings. The function
<strong>vscanf() is similar, but takes a pointer to an argument
list rather than a series of additional arguments. This
pointer should have been initialized with <strong>va_start</strong>().
The input conversions are performed according to the
fmt string; in general a character in the format string
must match a character in the input; however a space
character in the format string will match zero or more
"white space" characters in the input, i.e. spaces,
tabs or newlines. A conversion specification takes the
form of the character %, optionally followed by an
assignment suppression character ('*'), optionally followed by a numerical maximum field width, followed by a
conversion specification character. Each conversion
specification, unless it incorporates the assignment
suppression character, will assign a value to the variable pointed at by the next argument. Thus if there are
two conversion specifications in the fmt string, there
should be two additional pointer arguments. The
conversion characters are as follows:
;o x d
:Skip white space, then convert a number in base 8, 16 or 10 radix respectively. If a field width was supplied, take at most that many characters from the input. A leading minus sign will be recognized.
;f
:Skip white space, then convert a floating number in either conventional or scientific notation. The field width applies as above.
;s
:Skip white space, then copy a maximal length sequence of non-white-space characters. The pointer argument must be a pointer to char. The field width will limit the number of characters copied. The resultant string will be null-terminated.
;c
:Copy the next character from the input. The pointer argument is assumed to be a pointer to char. If a field width is specified, then copy that many characters. This differs from the s format in that white space does not terminate the character sequence.
The conversion characters o, x, u, d and f may be preceded by an l to indicate that the corresponding pointer argument is a pointer to long or double as appropriate. A preceding h will indicate that the pointer argument is a pointer to short rather than int.
<strong>Scanf</strong>() returns the number of successful conversions;
EOF is returned if end-of-file was seen before any
conversions were performed. Some examples are:
scanf("%d %s", &a, &s)
with input "12s"
will assign 12 to a, and "s" to s.
scanf("%4cd %lf", &c, &f)
with input " abcd -3.5"
will assign " abc" to c, and -3.5 to f.
==SEE ALSO==
fscanf, sscanf, printf, va_arg
==SYNOPSIS==
#include <stdio.h>
int scanf(char * fmt, ...)
int vscanf(char *, va_list ap);
==DESCRIPTION==
<strong>Scanf</strong>() performs formatted input ("de-editing") from
the stdin stream. Similar functions are available for
streams in general, and for strings. The function
<strong>vscanf() is similar, but takes a pointer to an argument
list rather than a series of additional arguments. This
pointer should have been initialized with <strong>va_start</strong>().
The input conversions are performed according to the
fmt string; in general a character in the format string
must match a character in the input; however a space
character in the format string will match zero or more
"white space" characters in the input, i.e. spaces,
tabs or newlines. A conversion specification takes the
form of the character %, optionally followed by an
assignment suppression character ('*'), optionally followed by a numerical maximum field width, followed by a
conversion specification character. Each conversion
specification, unless it incorporates the assignment
suppression character, will assign a value to the variable pointed at by the next argument. Thus if there are
two conversion specifications in the fmt string, there
should be two additional pointer arguments. The
conversion characters are as follows:
;o x d
:Skip white space, then convert a number in base 8, 16 or 10 radix respectively. If a field width was supplied, take at most that many characters from the input. A leading minus sign will be recognized.
;f
:Skip white space, then convert a floating number in either conventional or scientific notation. The field width applies as above.
;s
:Skip white space, then copy a maximal length sequence of non-white-space characters. The pointer argument must be a pointer to char. The field width will limit the number of characters copied. The resultant string will be null-terminated.
;c
:Copy the next character from the input. The pointer argument is assumed to be a pointer to char. If a field width is specified, then copy that many characters. This differs from the s format in that white space does not terminate the character sequence.
The conversion characters o, x, u, d and f may be preceded by an l to indicate that the corresponding pointer argument is a pointer to long or double as appropriate. A preceding h will indicate that the pointer argument is a pointer to short rather than int.
<strong>Scanf</strong>() returns the number of successful conversions;
EOF is returned if end-of-file was seen before any
conversions were performed. Some examples are:
scanf("%d %s", &a, &s)
with input "12s"
will assign 12 to a, and "s" to s.
scanf("%4cd %lf", &c, &f)
with input " abcd -3.5"
will assign " abc" to c, and -3.5 to f.
==SEE ALSO==
fscanf, sscanf, printf, va_arg
