Input/Output in C
An Introduction |
Prof. David Bernstein
|
Computer Science Department |
bernstdh@jmu.edu |
<stdio.h>
FILE
type for I/OSystem.in
, System.out
,
and System.err
, you can use the
FILE
variables stdin
,
stdout
, and stderr
fopen
and fclose
Functions:
FILE* fopen(const char* name, char* mode)
int fclose(FILE f)
name
is (a pointer to) the name of the filemode
is used to control the properties
of the file. A mode of "w" indicates that the file should be
opened for writing (i.e., output) and a mode of "r" indicates that
it should be opened for reading (i.e., input).printf
and scanf
functions (and variants discussed below) for this purposeprintf
Function:
scanf
Function:
l
for long
)- | Left justify |
0 | Pad with 0s instead of blanks |
+ | Prepend the sign |
d, i | Signed integer |
f | Floating point |
u | Unsigned integer |
s | String (i.e., pointer to an array of char ) |
c | Character |
o | Unsiged octal |
x | Unsigned hexadecimal |
e | Floating point in scientific notation |
p | Pointer (as a character sequence) |
n | Write the number of characters written so far to the given address |
An Example
fprintf
Function:
fscanf
Function:
FILE
to use for
input/outputsprintf
function:
printf
except that it does not
write to an output device; it stores what would be
printed in the given string
snprintf
function:
sprintf
except that the maximum number of
characters is specifiedfread
Function:
fwrite
Function: