String Classes <cstring> or <string>

Just wished to know if it is possible to write codes using the above two classes to do the following: (probably a function each)



1. Count the number of words and characters in the text file

2. Deleting strings from the array

3. Replace all occurrences of a string with a new string //something similar to what is available in Notepad.exe

AFAIK both <cstring> and <string> are not classes but header files:
<cstring> - This header file defines several functions to manipulate C strings and arrays.
<string> - This header introduces string types, character traits and a set of converting functions.