1. STL string class Programming Team 2/15/2006

2. string constructors string() = empty string string(int l, char ch) = string of length l, of repeated ch string(char* c-string) = string from c-string string(char* c-string, int l) = string from c- string, starts at 0, goes l characters long (substring basically) string(string oldString, int start = 0, int length = npos) = copy constructor, allows substring

3. string operators By default, all comparison operators work ==,, >= + operator is concatenation 4 versions: string + string string + c-string c-string + string string + char

4. string constants.npos => length of longest possible string, usually -1 Useful when doing find operations (is this substring in the string?) They will usually return npos if not in there

5. string methods c_str() Returns a pointer to a c-style string copy(char* array, int length, int index=0) Beginning at index, copy length number of chars from string into char array

6. string methods empty() Returns a boolean indicating whether or not the string is empty length() size() Return the number of characters in the string

7. string methods at(int index) [int index] Return the character in the string at a given position

8. string methods compare(string anotherString) Returns an integer, less than zero if calling string 0 if calling string > anotherString are defined in dictionary order (> farther back in dictionary) Can also call compare(char*) compare(int index, int length, string str) – compare whole str to substring of invoker compare(int index, int length, string str, int index2, int length2) – compare substring of str to substring of invoker compare(int index, int length, char* str, int length2 = npos) – compare substring of char array to substring of invoker

9. string methods substr(int index = 0, int length = npos) Returns substring of invoker

10. string methods append – Appends another string onto the back of the string Multiple versions append(string str) append(string str, int index, int length) append(char* array) append(char* array, int length) append(int length, char aChar)

11. string methods insert – Inserts another string into the middle of the invoker Multiple versions insert(int index, string str) insert(int index, string str, int index, int length) insert(int index, char* array) insert(int index, char* array, int length) insert(int index, int length, char aChar)

12. string methods Replace - Replaces another string into the middle of the invoker Multiple versions replace(int index, int length, string str) replace(int index, int length, string str, int index2, int length2) replace(int index, int length, char* array) replace(int index, int length, char* array, int length) replace(int index, int length, int length2, char aChar)

13. string methods erase – Deletes a portion of the string erase(int index = 0, int length = npos)

14. string methods int find(str anotherString) – returns the index of the first occurrence in the invoker of anotherString Versions to look for char*, to start search at different index than 0, to search for substrings of anotherString, to search for a char only int find_first_of(str charsToLookFor) – returns the index of the first occurrence in the invoker of any character in the string charsToLookFor Versions to use char* instead of string, to start search at different index than 0, to search for substrings of charsToLookFor, to search for a char only find_first_not_of - returns the index of the first occurrence in the invoker of any character not in the string charsToLookFor Versions to use char* instead of string, to start search at different index than 0, to search for substrings of charsToLookFor, to search for a char only

15. string methods rfind - returns the index of the last occurrence in the invoker of anotherString Versions to look for char*, to start search at different index than 0, to search for substrings of anotherString, to search for a char only int find_last_of(str charsToLookFor) – returns the index of the first occurrence in the invoker of any character in the string charsToLookFor Versions to use char* instead of string, to start search at different index than 0, to search for substrings of charsToLookFor, to search for a char only find_last_not_of - returns the index of the first occurrence in the invoker of any character not in the string charsToLookFor Versions to use char* instead of string, to start search at different index than 0, to search for substrings of charsToLookFor, to search for a char only

16. string methods Iterators – A way of traversing through a datastructure, an element at a time For strings, this is a char at a time begin() – Return an interator to the front of the string end() – Return an iterator to the very back of the string (past the end – usually used for checking if iterated far enough)

17. Iterators string aString = "helloworld"; string::iterator it = aString.begin(); while (it != aString.end()) { cout << "Iterator: " << *it << endl; it++; } cout << endl; for (int i = 0; i < aString.length(); i++) { cout << "For: " << aString[i] << endl; }

18. More information http://www.cprogramming.com/tutorial/strin g.html

19. Practice Problems