Topic: Strings Part 2 Points: 25

Goals

1. Learn proper usages of constant parameters.
2. Learn proper usages of constant functions.
3. Learn proper usages of constant return values.
4. Review use of pointers
5. Review dynamic memory
6. Make good use of encapsulation and information hiding

Instructions

1. Start with your files from the previous string assignment (or files given to you)
2. Make all paramters const that should not be changed.
3. Make all member functions const that should not change member variables.
4. Make all return values const that point or reference a member variable.
5. Be sure your header file can be included twice. Use:
   #ifndef STRING_H
   #define STRING_H
   class definition
   #endif
6. Be sure you have no duplicate code. (Use the functions you have written.)
7. Make all functions "this safe".
8. Implement the functions described below.
9. Be sure to check for NULL pointers in every possible scenario.

Functions to Add

1. subString - returns a String by value. It should take a starting index and a length.
   If the starting index is < 0 start a 0.
   If the starting index is > the length of the string return an empty string.
   If the length goes past the end of the string, just stop at the end.
   
2. equals - return true if the two values are equal. false otherwise. It should take a String, char*, char or int.
3. at - returns a char at the given index.
   It should take an integer as a parameter.
   If there is not a character at the given index return '\0'.
4. toUpper - should change all of the characters in the string to upper case.
5. toLower - should change all of the characters in the string to lower case.
6. trimStart - removes all of the white-space from the beginning of the String.
7. trimEnd - removes all of the white-space from the end of the String.
8. trim - removes all of the white-space from the beginning and end of the String.
9. replace - should take two parameters.
   Search for all occurrences of the first parameter and replace it with the second parameter.
   This function can be called in 16 ways.
   replace(String, String)
   replace(String, char*)
   replace(String, int)
   replace(String, char)
   replace(char*, String)
   replace(char*, char*)
   replace(char*, int)
   replace(char*, char)
   replace(int, String)
   replace(int, char*)
   replace(int, int)
   replace(int, char)
   replace(char, String)
   replace(char, char*)
   replace(char, int)
   replace(char, char)
   Be sure not to replace parts of the String that you just added
   

Hints

You should only have to write one replace function. See the Conversion Constructor Example
Sorry to tell you now but this was true for all of the functions you have written.