$5$:$23$

In this assignment, you will continue to work on the myString class from Assignment $2.$ You may start with the posted solution for Assignment $2$ if you wish.

Functionalities

In addition to the functionalities provided in Assignment $2,$ you should also provide the following methods. Here, "current string" refers to the string that the method is called with. I.e$.$ in s$.$length$(),$ s is the "current string."

char& operator $[]($int i$)$: returns a reference to the $i$ th character. Also provide a version which returns a reference to a constant. They should replace the corresponding at $()$ from the previous assignment.

myString& operator$+=($const myString& $s)$: concatenates $s$ to the current string. The current string is modified and a reference to it is returned.

myString operator$+($const myString& s$)$: returns a new string which is the current string concatenated with $s.$ The current string is not modified.

bool operator$==($const myString& $s)$: returns true if the two strings are equal, false otherwise.

bool operator$<mi\; id="EditorElement\_4225541">(</mi>$const myString& $s)$: returns true if the current string is lexicographically smaller than $s,$ and false otherwise. "Lexicographically smaller" means that "appears earlier in a dictionary." For example, "abc" is lexicographically smaller than "adc," and $"$he$"$ is lexicographically smaller than "hello."

The remaining comparisons: Hint: use the two operators above.

Also, provide the following friend functions:

$1$

operator$>>,$ operator$$: reads and writes into strings. For reading, note that you should ignore all whitespaces, and then read until the first whitespace. Use isspace in