Defined in header <stdio.h> (1) ​int scanf( const char *format, ... );​ (until C99) ​int scanf( const char *restrict format, ... );​ (since C99) (2) int fscanf( FILE *stream, const char *format, ... ); (until C99) int fscanf( FILE *restrict stream, const char *restrict format, ... ); (since C99) (3) int sscanf( const char *buffer, const char *format, ... ); (until C99) int sscanf( const char *restrict buff

A function declaration introduces an identifier that designates a function and, optionally, speicifies the types of the function parameters (the prototype). Function declarations (unlike definitions) may appear at block scope as well as file scope. Syntax In the declaration grammar of an function declaration, the type-specifier sequence, possibly modified by the declarator, designates the return type (which may be any type other than array or function type), and the declarator has one of two

Defined in header <stdlib.h> void srand( unsigned seed ); Seeds the pseudo-random number generator used by rand() with the value seed. If rand() is used before any calls to srand(), rand() behaves as if it was seeded with srand(1). Each time rand() is seeded with srand(), it must produce the same sequence of values. srand() is not guaranteed to be thread-safe. Parameters seed - the seed value Return value (none). Notes Generally speaking, the pseudo-random

Defined in header <stdlib.h> (1) size_t mbstowcs( wchar_t *dst, const char *src, size_t len) (until C99) size_t mbstowcs( wchar_t *restrict dst, const char *restrict src, size_t len) (since C99) errno_t mbstowcs_s(size_t *restrict retval, wchar_t *restrict dst, rsize_t dstsz, const char *restrict src, rsize_t len); (2) (since C11) 1) Converts a multibyte character string from the array whose first element is pointed to by src

The following chart contains all 128 ASCII decimal (dec), octal (oct), hexadecimal (hex) and character (ch) codes. dec oct hex ch dec oct hex ch dec oct hex ch dec oct hex ch 0 0 00 NUL (null) 32 40 20 (space) 64 100 40 @ 96 140 60 ` 1 1 01 SOH (start of header) 33 41 21 ! 65 101 41 A 97 141 61 a 2 2 02 STX (start of text) 34 42 22 " 66 102 42 B 98 142 62 b 3 3 03 ETX (end of text) 35 43 23

(See also type for type system overview and the list of type-related utilities that are provided by the C library). Boolean type _Bool (also accessible as the macro bool) - type, capable of holding one of the two values: 1 and 0 (also accessible as the macros true and false). Note that conversion to _Bool does not work the same as conversion to other integer types: (bool)0.5 evaluates to 1, whereas (int)0.5 evaluates to ​0​. (since C99) Character types signed char - type for signed

Defined in header <math.h> float rintf( float arg ); (1) (since C99) double rint( double arg ); (2) (since C99) long double rintl( long double arg ); (3) (since C99) Defined in header <tgmath.h> #define rint( arg ) (4) (since C99) Defined in header <math.h> long lrintf( float arg ); (5) (since C99) long lrint( double arg ); (6) (since C99) long lrintl( long double arg ); (7) (since C99) Defined in header <tgmat

Defined in header <wctype.h> int iswgraph( wint_t ch ); (since C95) Checks if the given wide character has a graphical representation, i.e. it is either a number (0123456789), an uppercase letter (ABCDEFGHIJKLMNOPQRSTUVWXYZ), a lowercase letter (abcdefghijklmnopqrstuvwxyz), a punctuation character(!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~) or any graphical character specific to the current C locale. Parameters ch - wide character Return value Non-zero value i

Defined in header <stdatomic.h> #define ATOMIC_FLAG_INIT /* unspecified */ (since C11) Expands to an expression that can be used to initialize atomic_flag type. The value atomic_flag that is not initialized using this macro is undefined. References C11 standard (ISO/IEC 9899:2011): 7.17.1/3 ATOMIC_FLAG_INIT (p: 273) 7.17.8/4 ATOMIC_FLAG_INIT (p: 285) See also ATOMIC_VAR_INIT (C11) initializes a new atomic object (function macro)

Defined in header <complex.h> #define _Complex_I /* unspecified */ (since C99) The _Complex_I macro expands to a value of type const float _Complex with the value of the imaginary unit. Notes This macro may be used when I is not available, such as when it has been undefined by the application. Unlike _Imaginary_I and CMPLX, use of this macro to construct a complex number may lose the sign of zero on the imaginary component. Example #include <stdio.h> #include