Character comparison strcmp

Char * strchr (const char * string, int C );

Searches for the position where character C appears for the first time in string. The null Terminator is also included in the search.

Returns a pointer pointing to the first position of character C in string. If no pointer is found, null is returned.

Char * strrchr (const char * string, int C );

Searches for the position where character c Last appears in string, that is, searches for string in reverse order, including the null Terminator.

Returns a pointer pointing to the last position of character C in the string. If no pointer is found, null is returned.

Char * strstr (const char * string, const char * strsearch );

Search for strsearch substrings in string.

Returns the pointer of the first position of the substring strsearch in the string. If the substring strsearch is not found, null is returned. If the substring strsearch is empty, the function returns the string value.

Int strcmp (const char * string1, const char * string2 );

Compare the string1 and string2 strings.

Return value <0, indicating that string1 is less than string2;
The return value is 0, indicating that string1 is equal to string2;
The return value is greater than 0, indicating that string1 is greater than string2.

Int stricmp (const char * string1, const char * string2 );

Compare the sizes of string1 and string2, which are different from those of strcmp.

The returned value is the same as that of strcmp.

Int strcmpi (const char * string1, const char * string2 );

It is equivalent to the stricmp function and only provides a backward compatible version.

Int strncmp (const char * string1, const char * string2, size_t count );

Compare the string1 and string2 strings. Only the previous count characters are compared. during the comparison, if the length of any string is smaller than count, count is replaced by the length of the shorter string. at this time, if the two strings are equal to the first character, the shorter string is smaller.

Return value <0, indicating the substring of string1 smaller than string2;
The return value is 0, indicating that the substring of string1 is equal to the substring of string2;
The return value is greater than 0, indicating that the substring of string1 is greater than that of string2.

Int strnicmp (const char * string1, const char * string2, size_t count );

Compare the string1 and string2 strings with only the previous count characters. Different from strncmp, compare their lower-case letter versions.

The returned value is the same as that of strncmp.

Char * strtok (char * strtoken, const char * strdelimit );

Find the next tag in the strtoken string. The strdelimit Character Set specifies the delimit that may be encountered in the current query call.

Returns a pointer pointing to the next tag found in the strtoken. If no tag is found, null is returned. The strtoken content will be modified each time the strtoken is called, replacing each delimiter encountered with a null character.

For memory block comparison functions, refer to the following:
Void * memchr (const void * Buf, int C, size_t count );

Search for the position of the first occurrence of the character C in the count byte before the Buf. Find the character C or search for the Count byte, and stop searching.

If the operation succeeds, the position pointer of C appears for the first time in Buf. Otherwise, null is returned.

Void * _ memccpy (void * DEST, const void * SRC, int C, size_t count );

Copy 0 or multiple bytes from SRC to DeST. When character C is copied or count is copied, the copy is stopped.

If character C is copied, the function returns a pointer next to the character. Otherwise, null is returned.

Int memcmp (const void * buf1, const void * buf2, size_t count );

Compare the size of the first count bytes of buf1 and buf2.

Return value <0, indicating that buf1 is smaller than buf2;
The returned value is 0, indicating that buf1 is equal to buf2;
The returned value is greater than 0, indicating that buf1 is greater than buf2.

Int memicmp (const void * buf1, const void * buf2, size_t count );

Compare the Count bytes before buf1 and buf2. Unlike memcmp, It is case insensitive.

The return value is the same as the preceding one.