Common C string processing functions

1. Function Name: stpcpy
Function: copy one string to another.

Usage: char * stpcpy (char * Destin, char * Source );

2. Function Name: strcat
Function: String concatenation Function

Usage: char * strcat (char * Destin, char * Source );

3. Function Name: strchr
Function: searches for the first matching of a given character in a string.

4. Function Name: strcmp
Function: String comparison
Usage:

Int strcmp (char * str1, char * str2 );

5. Function Name: strncmpi
Function: compares a part of a string with another string regardless of case.

Usage: int strncmpi (char * str1, char * str2, unsigned maxlen );

6. Function Name: strcpy
Function: Copy strings

Usage: char * strcpy (char * str1, char * str2 );

7. Function Name: strcspns
Function: Search for the content segment of the first given character set in the string.

Usage: int strcspn (char * str1, char * str2 );

8. Function Name: strdup
Function: copy the string to the new position.

Usage: char * strdup (char * Str );

9. Function Name: stricmp
Function: Compares two strings in upper and lower case insensitive mode.

Usage: int stricmp (char * str1, char * str2 );

10. Function Name: strerror
Function: returns a pointer to the error message string.

Usage: char * strerror (INT errnum );

11. Function Name: strcmpi
Function: compares a string with another string, regardless of case.

Usage: int strcmpi (char * str1, char * str2 );

12. Function Name: strncmp
Function: String comparison

Usage: int strncmp (char * str1, char * str2, int maxlen );

13. Function Name: strncmpi
Function: compares a part of a string with a part of another string, regardless of case.

Usage: int strncmpi (char * str1, char * str2 );

14. Function Name: strncpy
Function: Copy strings

Usage: char * strncpy (char * Destin, char * Source, int maxlen );

15. Function Name: strnset
Function: Set all characters in a string to a specified character.

Usage: char * strnset (char * STR, char CH, unsigned N );

16. Function Name: strpbrk
Function: searches for characters in a given character set in a string.

Usage: char * strpbrk (char * str1, char * str2 );

17. Function Name: strrchr
Function: Find the last occurrence of a specified character in the string.

Usage: char * strrchr (char * STR, char C );

18. Function Name: strrev
Power: String reversal

Usage: char * strrev (char * Str );

19. Function Name: strspns
Function: finds the first occurrence of a subset of a specified character set in a string.

Usage: int strspn (char * str1, char * str2 );

20. Function Name: strstr
Function: Search for the first appearance of a specified string in the string.

Usage: char * strstr (char * str1, char * str2 );

21. Function Name: strtodd
Function: converts a string to a double value.

Usage: Double strtodd (char * STR, char ** endptr );

22. Function Name: strtok
Function: searches for words separated by the delimiters specified in the second string.

Usage: char * strtok (char * str1, char * str2 );
ProgramExample:

23. Function Name: strtol
Function: converts a string to a long integer.

Usage: Long strtol (char * STR, char ** endptr, int base );

24. Function Name: strupr
Function: converts lowercase letters in a string to uppercase letters.

Usage: char * strupr (char * Str );

25. Function Name: swab
Function: swap byte

Usage: void swab (char * From, char * To, int nbytes );