Programming C

Char * strcpy function (char * dest, const char * src) copies the string pointed to by src to dest.

Strncpy char * (char * dest, const char * src, size_t n) copies up to n copies to n characters from the string pointed to by src to dest. In case the length of the src is smaller

The function size_t strcspn (const char * str1, const char * str2) calculates the length of the character segment of string str1 without containing the characters in str2.

The function char * strerror (int errnum) searches for an internal array for errnum error numbers and returns a pointer to a string of error messages.

The function size_t strlen (const char * str) calculates the length of str string (not including the ending null character).

Char * strpbrk (const char * str1, const char * str2) finds the first character in str1 string that connects any character specified in str2. (not including null ending

Char * strrchr (const char * str, int c) looks for the last occurrence of the character c (an unsigned char) in the string pointed to by parameter str.

Function size_t strspn (const char * str1, const char * str2) calculates the length of the first character segment of the str1 string containing the characters in str2

Char * strtok function (char * str, const char * delim) divides the string str into a sequence of tokens separately separated by delim separators (eg comma, ...).

The function size_t strxfrm (char * dest, const char * src, size_t n) transforms the first n characters of the src string into the current locale and places them in dest string.

The printf () function in the Standard C library sends formatted output to a stdout.

The file header named time.h in Standard Library C defines four variable types, two macros and various functions for date and time operations.

Char * getenv (const char * name) function searches the environment string pointed to by the name parameter and returns the value associated with that string.

The int system (const char * command) function passes the command name or program name specified by the command to the host environment to be executed by the Command processor and

Void function * bsearch (const void * key, const void * base, nitems, size, int (* compar) (const void *, const void *)) looks for an array of nitems objects, its original member

Void qsort function (void * base, so-phan-tu, kich-co, int (* compar) (const void *, const void *)) arranges an array.

The function int abs (int x) returns the absolute value of integer x.

Div_t div function (int numer, int denom) divides numer numerator for denom.

Function long int labs (long int x) returns the absolute value of x.

The div_t div function (long int numer, long int denom) divides the numerator numer to denom.