C Reference Card (ANSI)

C Reference Card (ANSI)
Constants
Flow of Control
long (su?x)
L or l
statement terminator
;
Program Structure/Functions
?oat (su?x)
F or f
block delimeters
{
}
type fnc(type
exponential form
e
exit from switch, while, do, for
break
1 ,. . . )
function declarations
type name
external variable declarations
octal (pre?x zero)
0
next iteration of while, do, for
continue
main() {
main routine
hexadecimal (pre?x zero-ex)
0x or 0X
go to
goto label
declarations
local variable declarations
character constant (char, octal, hex)
'a', '\ooo', '\xhh'
label
label :
statements
newline, cr, tab, backspace
\n, \r, \t, \b
return value from function
return expr
}
special characters
\\, \?, \', \"
Flow Constructions
type fnc(arg
string constant (ends with '\0')
"abc. . . de"
if statement
if (expr )
statement
1 ,. . . ) {
function de?nition
declarations
local variable declarations
else if (expr )
statement
Pointers, Arrays & Structures
statements
else
statement
return value;
declare pointer to type
type *name
while statement
while (expr )
statement
}
declare function returning pointer to type type *f()
for statement
for (expr
/*
*/
comments
declare pointer to function returning type type (*pf)()
1 ; expr 2 ; expr 3 )
statement
main(int argc, char *argv[])
main with args
generic pointer type
void *
do statement
do
statement
exit(arg )
terminate execution
null pointer
NULL
while(expr );
C Preprocessor
object pointed to by pointer
*pointer
switch statement
switch (expr ) {
address of object name
&name
case const 1: statement 1 break;
include library ?le
#include <?lename>
array
name[dim ]
case const 2: statement 2 break;
include user ?le
#include "?lename"
multi-dim array
name[dim 1][dim2]. . .
default: statement
replacement text
#define name text
Structures
}
replacement macro
#define name(var ) text
struct tag {
structure template
Example. #define max(A,B) ((A)>(B) ? (A) : (B))
declarations
declaration of members
ANSI Standard Libraries
unde?ne
#undef name
};
<assert.h>
<ctype.h>
<errno.h>
<float.h>
<limits.h>
quoted string in replace
#
create structure
struct tag name
<locale.h>
<math.h>
<setjmp.h>
<signal.h>
<stdarg.h>
concatenate args and rescan
##
member of structure from template
name.member
<stddef.h>
<stdio.h>
<stdlib.h>
<string.h>
<time.h>
conditional execution
#if, #else, #elif, #endif
member of pointed to structure
pointer -> member
is name de?ned, not de?ned?
#ifdef, #ifndef
Character Class Tests <ctype.h>
Example. (*p).x and p->x are the same
name de?ned?
defined(name )
single value, multiple type structure
union
alphanumeric?
isalnum(c)
line continuation char
\
bit ?eld with b bits
member : b
alphabetic?
isalpha(c)
Data Types/Declarations
Operators (grouped by precedence)
control character?
iscntrl(c)
decimal digit?
isdigit(c)
character (1 byte)
char
structure member operator
name.member
printing character (not incl space)?
isgraph(c)
integer
int
structure pointer
pointer ->member
lower case letter?
islower(c)
?oat (single precision)
float
printing character (incl space)?
increment, decrement
isprint(c)
++, --
?oat (double precision)
double
printing char except space, letter, digit? ispunct(c)
plus, minus, logical not, bitwise not
+, -, !, ~
short (16 bit integer)
short
space, formfeed, newline, cr, tab, vtab?
isspace(c)
indirection via pointer, address of object *pointer , &name
long (32 bit integer)
long
upper case letter?
isupper(c)
cast expression to type
(type) expr
positive and negative
signed
hexadecimal digit?
size of an object
isxdigit(c)
sizeof
only positive
unsigned
convert to lower case?
tolower(c)
pointer to int, float,. . .
*int, *float,. . .
multiply, divide, modulus (remainder)
*, /, %
convert to upper case?
toupper(c)
enumeration constant
enum
add, subtract
+, -
constant (unchanging) value
const
String Operations <string.h>
declare external variable
left, right shift [bit ops]
<<, >>
extern
s,t are strings, cs,ct are constant strings
register variable
register
comparisons
>, >=, <, <=
length of s
strlen(s)
local to source ?le
static
comparisons
==, !=
copy ct to s
strcpy(s,ct)
no value
void
bitwise and
&
up to n chars
strncpy(s,ct,n)
structure
struct
concatenate ct after s
strcat(s,ct)
create name by data type
typedef typename
bitwise exclusive or
^
up to n chars
strncat(s,ct,n)
size of an object (type is size_t)
sizeof object
bitwise or (incl)
|
compare cs to ct
strcmp(cs,ct)
size of a data type (type is size_t)
sizeof(type name)
logical and
&&
only ?rst n chars
strncmp(cs,ct,n)
Initialization
logical or
||
pointer to ?rst c in cs
strchr(cs,c)
pointer to last c in cs
strrchr(cs,c)
initialize variable
conditional expression
expr
type name=value
1 ? expr 2 : expr 3
copy n chars from ct to s
memcpy(s,ct,n)
initialize array
type name[]={value
assignment operators
1 ,. . . }
+=, -=, *=, . . .
copy n chars from ct to s (may overlap) memmove(s,ct,n)
initialize char string
char name[]="string "
expression evaluation separator
,
compare n chars of cs with ct
memcmp(cs,ct,n)
pointer to ?rst c in ?rst n chars of cs
memchr(cs,c,n)
Unary operators, conditional expression and assignment oper-
put c into ?rst n chars of cs
memset(s,c,n)
ators group right to left; all others group left to right.
c 1999 Joseph H. Silverman Permissions on back. v1.3
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C Reference Card (ANSI)
Standard Utility Functions <stdlib.h>
Integer Type Limits <limits.h>
absolute value of int n
abs(n)
The numbers given in parentheses are typical values for the
Input/Output <stdio.h>
absolute value of long n
labs(n)
constants on a 32-bit Unix system.
quotient and remainder of ints n,d
div(n,d)
CHAR_BIT
bits in char
(8)
Standard I/O
retursn structure with div_t.quot and div_t.rem
CHAR_MAX
max value of char
(127 or 255)
standard input stream
stdin
quotient and remainder of longs n,d
ldiv(n,d)
CHAR_MIN
min value of char
(?128 or 0)
standard output stream
stdout
returns structure with ldiv_t.quot and ldiv_t.rem
INT_MAX
max value of int
(+32,767)
standard error stream
stderr
pseudo-random integer [0,RAND_MAX]
rand()
INT_MIN
min value of int
(?32,768)
end of ?le
EOF
set random seed to n
srand(n)
LONG_MAX
max value of long
(+2,147,483,647)
get a character
getchar()
terminate program execution
exit(status)
LONG_MIN
min value of long
(?2,147,483,648)
print a character
putchar(chr )
pass string s to system for execution
system(s)
SCHAR_MAX
max value of signed char
(+127)
print formatted data
printf("format ",arg 1,. . . )
Conversions
SCHAR_MIN
min value of signed char
(?128)
print to string s
sprintf(s,"format ",arg 1,. . . )
convert string s to double
atof(s)
SHRT_MAX
max value of short
(+32,767)
read formatted data
scanf("format ",&name 1,. . . )
convert string s to integer
atoi(s)
SHRT_MIN
min value of short
(?32,768)
read from string s
sscanf(s,"format ",&name 1,. . . )
convert string s to long
atol(s)
UCHAR_MAX
max value of unsigned char
(255)
read line to string s (< max chars)
gets(s,max)
convert pre?x of s to double
strtod(s,endp)
UINT_MAX
max value of unsigned int
(65,535)
print string s
puts(s)
convert pre?x of s (base b) to long
strtol(s,endp,b)
ULONG_MAX
max value of unsigned long
(4,294,967,295)
File I/O
same, but unsigned long
strtoul(s,endp,b)
USHRT_MAX
max value of unsigned short
(65,536)
declare ?le pointer
FILE *fp
Storage Allocation
pointer to named ?le
fopen("name ","mode ")
allocate storage
malloc(size), calloc(nobj,size)
Float Type Limits <float.h>
modes: r (read), w (write), a (append)
change size of object
realloc(pts,size)
FLT_RADIX
radix of exponent rep
(2)
get a character
getc(fp)
deallocate space
free(ptr)
FLT_ROUNDS
?oating point rounding mode
write a character
putc(chr ,fp)
Array Functions
FLT_DIG
decimal digits of precision
(6)
write to ?le
fprintf(fp,"format ",arg 1,. . . )
search array for key
bsearch(key,array,n,size,cmp())
FLT_EPSILON
smallest x so 1.0 + x = 1.0
(10 5
?
)
read from ?le
fscanf(fp,"format ",arg 1,. . . )
sort array ascending order
qsort(array,n,size,cmp())
FLT_MANT_DIG
number of digits in mantissa
close ?le
fclose(fp)
FLT_MAX
maximum ?oating point number
(1037)
non-zero if error
ferror(fp)
Time and Date Functions <time.h>
FLT_MAX_EXP
maximum exponent
non-zero if EOF
feof(fp)
FLT_MIN
minimum ?oating point number
(10 37
?
)
read line to string s (< max chars)
fgets(s,max,fp )
processor time used by program
clock()
FLT_MIN_EXP
minimum exponent
write string s
fputs(s,fp )
Example. clock()/CLOCKS_PER_SEC is time in seconds
DBL_DIG
decimal digits of precision
(10)
Codes for Formatted I/O: "%-+ 0w.pmc"
current calendar time
time()
9
-
left justify
time2-time1 in seconds (double)
difftime(time2 ,time1)
DBL_EPSILON
smallest x so 1.0 + x = 1.0
(10? )
+
print with sign
arithmetic types representing times
clock_t,time_t
DBL_MANT_DIG
number of digits in mantissa
space print space if no sign
structure type for calendar time comps
tm
DBL_MAX
max double ?oating point number
(1037)
0
pad with leading zeros
tm_sec
seconds after minute
DBL_MAX_EXP
maximum exponent
37
w
min ?eld width
tm_min
minutes after hour
DBL_MIN
min double ?oating point number
(10?
)
p
precision
tm_hour
hours since midnight
DBL_MIN_EXP
minimum exponent
m
conversion character:
tm_mday
day of month
h
short,
l
long,
L
long double
tm_mon
months since January
c
conversion character:
tm_year
years since 1900
d,i integer
u
unsigned
tm_wday
days since Sunday
c
single char
s
char string
tm_yday
days since January 1
f
double
e,E exponential
tm_isdst
Daylight Savings Time ?ag
o
octal
x,X hexadecimal
convert local time to calendar time
mktime(tp)
p
pointer
n
number of chars written
convert time in tp to string
asctime(tp)
g,G same as f or e,E depending on exponent
convert calendar time in tp to local time ctime(tp)
Variable Argument Lists
convert calendar time to GMT
gmtime(tp)
<stdarg.h>
convert calendar time to local time
localtime(tp)
declaration of pointer to arguments
va_list name;
format date and time info
strftime(s,smax,"format ",tp)
initialization of argument pointer
va_start(name ,lastarg )
tp is a pointer to a structure of type tm
lastarg is last named parameter of the function
Mathematical Functions <math.h>
access next unamed arg, update pointer
va_arg(name ,type)
call before exiting function
va_end(name )
Arguments and returned values are double
trig functions
sin(x), cos(x), tan(x)
inverse trig functions
asin(x), acos(x), atan(x)
arctan(y/x)
atan2(y,x)
hyperbolic trig functions
sinh(x), cosh(x), tanh(x)
May 1999 v1.3. Copyright c 1999 Joseph H. Silverman
exponentials & logs
exp(x), log(x), log10(x)
exponentials & logs (2 power)
Permission is granted to make and distribute copies of this card pro-
ldexp(x,n), frexp(x,*e)
vided the copyright notice and this permission notice are preserved on
division & remainder
modf(x,*ip), fmod(x,y)
all copies.
powers
pow(x,y), sqrt(x)
Send comments and corrections to J.H. Silverman, Math. Dept., Brown
rounding
ceil(x), floor(x), fabs(x)
Univ., Providence, RI 02912 USA. jhs@math.brown.edu
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