Defined in header <stdio.h> int fseek( FILE *stream, long offset, int origin ); Sets the file position indicator for the file stream stream to the value pointed to by offset. If the stream is open in binary mode, the new position is exactly offset bytes measured from the beginning of the file if origin is SEEK_SET, from the current file position if origin is SEEK_CUR, and from the end of the file if origin is SEEK_END. Binary streams are not required to support SEEK_END, in

Defined in header <wctype.h> int iswlower( wint_t ch ); (since C95) Checks if the given wide character is a lowercase letter, i.e. one of abcdefghijklmnopqrstuvwxyz or any lowercase letter specific to the current locale. Parameters ch - wide character Return value Non-zero value if the wide character is an lowercase letter, zero otherwise. Example #include <stdio.h> #include <wchar.h> #include <wctype.h> #include <locale.h> int m

Defined in header <stdlib.h> int wctomb( char *s, wchar_t wc ); (1) errno_t wctomb_s(int *restrict status, char *restrict s, rsize_t ssz, wchar_t wc); (2) (since C11) 1) Converts a wide character wc to multibyte encoding and stores it (including any shift sequences) in the char array whose first element is pointed to by s. No more than MB_CUR_MAX characters are stored. If wc is the null character, the null byte is written to s, preceded by any shift sequences neces

Assignment and compound assignment operators are binary operators that modify the variable to their left using the value to their right. Operator Operator name Example Description Equivalent of = basic assignment a = b a becomes equal to b N/A += addition assignment a += b a becomes equal to the addition of a and b a = a + b -= subtraction assignment a -= b a becomes equal to the subtraction of b from a a = a - b *= multiplication assignment a *= b

Usage void type: as the declaration of the incomplete type void: in a function with no parameter or no return value

Defined in header <stdlib.h> double atof( const char* str ); Interprets an floating point value in a byte string pointed to by str. Function discards any whitespace characters (as determined by std::isspace()) until first non-whitespace character is found. Then it takes as many characters as possible to form a valid floating point representation and converts them to floating point value. The valid floating point value can be one of the following: decimal floating point expr

Defined in header <complex.h> float complex catanf( float complex z ); (1) (since C99) double complex catan( double complex z ); (2) (since C99) long double complex catanl( long double complex z ); (3) (since C99) Defined in header <tgmath.h> #define atan( z ) (4) (since C99) 1-3) Computes the complex arc tangent of z with branch cuts outside the interval [−i,+i] along the imaginary axis. 4) Type-generic macro: If z has type long

Defined in header <math.h> float logf( float arg ); (1) (since C99) double log( double arg ); (2) long double logl( long double arg ); (3) (since C99) Defined in header <tgmath.h> #define log( arg ) (4) (since C99) 1-3) Computes the natural (base e) logarithm of arg. 4) Type-generic macro: If arg has type long double, logl is called. Otherwise, if arg has integer type or the type double, log is called. Otherwise, logf is called. I

Defined in header <math.h> float tanf( float arg ); (1) (since C99) double tan( double arg ); (2) long double tanl( long double arg ); (3) (since C99) Defined in header <tgmath.h> #define tan( arg ) (4) (since C99) 1-3) Computes the tangent of arg (measured in radians). 4) Type-generic macro: If the argument has type long double, tanl is called. Otherwise, if the argument has integer type or the type double, tan is called. Otherwi

Defined in header <uchar.h> size_t c32rtomb( char* s, char32_t c32, mbstate_t* ps ); (since C11) Converts a 32-bit wide character to its narrow multibyte representation. If s is not a null pointer, the function determines the number of bytes necessary to store the multibyte character representation of c32 (including any shift sequences), and stores the multibyte character representation in the character array whose first element is pointed to by s. At most MB_CUR_MAX bytes