All C inbuilt functions which are declared in string.h header file are given below. The source code for string.h header file is also given below for your reference.
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List of inbuilt C functions in string.h file:
| S.no |
string functions
|
Description
|
| 1 | strcat(str1, str2) | Concatenates str2 at the end of str1. |
| 2 | strcpy(str1, str2) | Copies str2 into str1 |
| 3 | strlen(strl) | gives the length of str1. |
| 4 | strcmp(str1, str2) | Returns 0 if str1 is same as str2. Returns <0 if strl < str2. Returns >0 if str1 > str2. |
| 5 | strchr(str1,char) | Returns pointer to first occurrence of char in str1. |
| 6 | strstr(str1, str2) | Returns pointer to first occurrence of str2 in str1. |
| 7 | strcmpi(str1,str2) | Same as strcmp() function. But, this function negotiates case. “A” and “a” are treated as same. |
| 8 | strdup() | duplicates the string |
| 9 | strlwr() | converts string to lowercase |
| 10 | strncat() | appends a portion of string to another |
| 11 | strncpy() | copies given number of characters of one string to another |
| 12 | strrchr() | last occurrence of given character in a string is found |
| 13 | strrev() | reverses the given string |
| 14 | strset() | sets all character in a string to given character |
| 15 | strupr() | converts string to uppercase |
| 16 | strtok() | tokenizing given string using delimiter |
| 17 | memset() | It is used to initialize a specified number of bytes to null or any other value in the buffer |
| 18 | memcpy() | It is used to copy a specified number of bytes from one memory to another |
| 19 | memmove() | It is used to copy a specified number of bytes from one memory to another or to overlap on same memory. |
| 20 | memcmp() | It is used to compare specified number of characters from two buffers |
| 21 | memicmp() | It is used to compare specified number of characters from two buffers regardless of the case of the characters |
| 22 | memchr() | It is used to locate the first occurrence of the character in the specified string |
Source code for string.h header file:
Please find the source code for string.h header file below. This code is taken from DevC++ compiler files for your reference.
/*
* string.h
* This file has no copyright assigned and is placed in the Public Domain.
* This file is a part of the mingw-runtime package.
* No warranty is given; refer to the file DISCLAIMER within the package.
*
* Definitions for memory and string functions.
*
*/
#ifndef _STRING_H_
#define _STRING_H_
/* All the headers include this file. */
#include <_mingw.h>
/*
* Define size_t, wchar_t and NULL
*/
#define __need_size_t
#define __need_wchar_t
#define __need_NULL
#ifndef RC_INVOKED
#include <stddef.h>
#endif /* Not RC_INVOKED */
#ifndef RC_INVOKED
#ifdef __cplusplus
extern "C" {
#endif
/*
* Prototypes of the ANSI Standard C library string functions.
*/
_CRTIMP void* __cdecl memchr (const void*, int, size_t) __MINGW_ATTRIB_PURE;
_CRTIMP int __cdecl memcmp (const void*, const void*, size_t) __MINGW_ATTRIB_PURE;
_CRTIMP void* __cdecl memcpy (void*, const void*, size_t);
_CRTIMP void* __cdecl memmove (void*, const void*, size_t);
_CRTIMP void* __cdecl memset (void*, int, size_t);
_CRTIMP char* __cdecl strcat (char*, const char*);
_CRTIMP char* __cdecl strchr (const char*, int) __MINGW_ATTRIB_PURE;
_CRTIMP int __cdecl strcmp (const char*, const char*) __MINGW_ATTRIB_PURE;
_CRTIMP int __cdecl strcoll (const char*, const char*); /* Compare using locale */
_CRTIMP char* __cdecl strcpy (char*, const char*);
_CRTIMP size_t __cdecl strcspn (const char*, const char*) __MINGW_ATTRIB_PURE;
_CRTIMP char* __cdecl strerror (int); /* NOTE: NOT an old name wrapper. */
_CRTIMP size_t __cdecl strlen (const char*) __MINGW_ATTRIB_PURE;
_CRTIMP char* __cdecl strncat (char*, const char*, size_t);
_CRTIMP int __cdecl strncmp (const char*, const char*, size_t) __MINGW_ATTRIB_PURE;
_CRTIMP char* __cdecl strncpy (char*, const char*, size_t);
_CRTIMP char* __cdecl strpbrk (const char*, const char*) __MINGW_ATTRIB_PURE;
_CRTIMP char* __cdecl strrchr (const char*, int) __MINGW_ATTRIB_PURE;
_CRTIMP size_t __cdecl strspn (const char*, const char*) __MINGW_ATTRIB_PURE;
_CRTIMP char* __cdecl strstr (const char*, const char*) __MINGW_ATTRIB_PURE;
_CRTIMP char* __cdecl strtok (char*, const char*);
_CRTIMP size_t __cdecl strxfrm (char*, const char*, size_t);
#ifndef __STRICT_ANSI__
/*
* Extra non-ANSI functions provided by the CRTDLL library
*/
_CRTIMP char* __cdecl _strerror (const char *);
_CRTIMP void* __cdecl _memccpy (void*, const void*, int, size_t);
_CRTIMP int __cdecl _memicmp (const void*, const void*, size_t);
_CRTIMP char* __cdecl _strdup (const char*) __MINGW_ATTRIB_MALLOC;
_CRTIMP int __cdecl _strcmpi (const char*, const char*);
_CRTIMP int __cdecl _stricmp (const char*, const char*);
_CRTIMP int __cdecl _stricoll (const char*, const char*);
_CRTIMP char* __cdecl _strlwr (char*);
_CRTIMP int __cdecl _strnicmp (const char*, const char*, size_t);
_CRTIMP char* __cdecl _strnset (char*, int, size_t);
_CRTIMP char* __cdecl _strrev (char*);
_CRTIMP char* __cdecl _strset (char*, int);
_CRTIMP char* __cdecl _strupr (char*);
_CRTIMP void __cdecl _swab (const char*, char*, size_t);
#ifdef __MSVCRT__
_CRTIMP int __cdecl _strncoll(const char*, const char*, size_t);
_CRTIMP int __cdecl _strnicoll(const char*, const char*, size_t);
#endif
#ifndef _NO_OLDNAMES
/*
* Non-underscored versions of non-ANSI functions. They live in liboldnames.a
* and provide a little extra portability. Also a few extra UNIX-isms like
* strcasecmp.
*/
_CRTIMP void* __cdecl memccpy (void*, const void*, int, size_t);
_CRTIMP int __cdecl memicmp (const void*, const void*, size_t);
_CRTIMP char* __cdecl strdup (const char*) __MINGW_ATTRIB_MALLOC;
_CRTIMP int __cdecl strcmpi (const char*, const char*);
_CRTIMP int __cdecl stricmp (const char*, const char*);
__CRT_INLINE int __cdecl
strcasecmp (const char * __sz1, const char * __sz2)
{return _stricmp (__sz1, __sz2);}
_CRTIMP int __cdecl stricoll (const char*, const char*);
_CRTIMP char* __cdecl strlwr (char*);
_CRTIMP int __cdecl strnicmp (const char*, const char*, size_t);
__CRT_INLINE int __cdecl
strncasecmp (const char * __sz1, const char * __sz2, size_t __sizeMaxCompare)
{return _strnicmp (__sz1, __sz2, __sizeMaxCompare);}
_CRTIMP char* __cdecl strnset (char*, int, size_t);
_CRTIMP char* __cdecl strrev (char*);
_CRTIMP char* __cdecl strset (char*, int);
_CRTIMP char* __cdecl strupr (char*);
#ifndef _UWIN
_CRTIMP void __cdecl swab (const char*, char*, size_t);
#endif /* _UWIN */
#endif /* _NO_OLDNAMES */
#endif /* Not __STRICT_ANSI__ */
#ifndef _WSTRING_DEFINED
/*
* Unicode versions of the standard calls.
* Also in wchar.h, where they belong according to ISO standard.
*/
_CRTIMP wchar_t* __cdecl wcscat (wchar_t*, const wchar_t*);
_CRTIMP wchar_t* __cdecl wcschr (const wchar_t*, wchar_t);
_CRTIMP int __cdecl wcscmp (const wchar_t*, const wchar_t*);
_CRTIMP int __cdecl wcscoll (const wchar_t*, const wchar_t*);
_CRTIMP wchar_t* __cdecl wcscpy (wchar_t*, const wchar_t*);
_CRTIMP size_t __cdecl wcscspn (const wchar_t*, const wchar_t*);
/* Note: _wcserror requires __MSVCRT_VERSION__ >= 0x0700. */
_CRTIMP size_t __cdecl wcslen (const wchar_t*);
_CRTIMP wchar_t* __cdecl wcsncat (wchar_t*, const wchar_t*, size_t);
_CRTIMP int __cdecl wcsncmp(const wchar_t*, const wchar_t*, size_t);
_CRTIMP wchar_t* __cdecl wcsncpy(wchar_t*, const wchar_t*, size_t);
_CRTIMP wchar_t* __cdecl wcspbrk(const wchar_t*, const wchar_t*);
_CRTIMP wchar_t* __cdecl wcsrchr(const wchar_t*, wchar_t);
_CRTIMP size_t __cdecl wcsspn(const wchar_t*, const wchar_t*);
_CRTIMP wchar_t* __cdecl wcsstr(const wchar_t*, const wchar_t*);
_CRTIMP wchar_t* __cdecl wcstok(wchar_t*, const wchar_t*);
_CRTIMP size_t __cdecl wcsxfrm(wchar_t*, const wchar_t*, size_t);
#ifndef __STRICT_ANSI__
/*
* Unicode versions of non-ANSI string functions provided by CRTDLL.
*/
/* NOTE: _wcscmpi not provided by CRTDLL, this define is for portability */
#define _wcscmpi _wcsicmp
_CRTIMP wchar_t* __cdecl _wcsdup (const wchar_t*);
_CRTIMP int __cdecl _wcsicmp (const wchar_t*, const wchar_t*);
_CRTIMP int __cdecl _wcsicoll (const wchar_t*, const wchar_t*);
_CRTIMP wchar_t* __cdecl _wcslwr (wchar_t*);
_CRTIMP int __cdecl _wcsnicmp (const wchar_t*, const wchar_t*, size_t);
_CRTIMP wchar_t* __cdecl _wcsnset (wchar_t*, wchar_t, size_t);
_CRTIMP wchar_t* __cdecl _wcsrev (wchar_t*);
_CRTIMP wchar_t* __cdecl _wcsset (wchar_t*, wchar_t);
_CRTIMP wchar_t* __cdecl _wcsupr (wchar_t*);
#ifdef __MSVCRT__
_CRTIMP int __cdecl _wcsncoll(const wchar_t*, const wchar_t*, size_t);
_CRTIMP int __cdecl _wcsnicoll(const wchar_t*, const wchar_t*, size_t);
#if __MSVCRT_VERSION__ >= 0x0700
_CRTIMP wchar_t* __cdecl _wcserror(int);
_CRTIMP wchar_t* __cdecl __wcserror(const wchar_t*);
#endif
#endif
#ifndef _NO_OLDNAMES
/* NOTE: There is no _wcscmpi, but this is for compatibility. */
int __cdecl wcscmpi (const wchar_t * __ws1, const wchar_t * __ws2);
__CRT_INLINE int __cdecl
wcscmpi (const wchar_t * __ws1, const wchar_t * __ws2)
{return _wcsicmp (__ws1, __ws2);}
_CRTIMP wchar_t* __cdecl wcsdup (const wchar_t*);
_CRTIMP int __cdecl wcsicmp (const wchar_t*, const wchar_t*);
_CRTIMP int __cdecl wcsicoll (const wchar_t*, const wchar_t*);
_CRTIMP wchar_t* __cdecl wcslwr (wchar_t*);
_CRTIMP int __cdecl wcsnicmp (const wchar_t*, const wchar_t*, size_t);
_CRTIMP wchar_t* __cdecl wcsnset (wchar_t*, wchar_t, size_t);
_CRTIMP wchar_t* __cdecl wcsrev (wchar_t*);
_CRTIMP wchar_t* __cdecl wcsset (wchar_t*, wchar_t);
_CRTIMP wchar_t* __cdecl wcsupr (wchar_t*);
#endif /* Not _NO_OLDNAMES */
#endif /* Not strict ANSI */
#define _WSTRING_DEFINED
#endif /* _WSTRING_DEFINED */
#ifdef __cplusplus
}
#endif
#endif /* Not RC_INVOKED */
#endif /* Not _STRING_H_ */