Mutable strings: contract (3)
Possible contract (continued):
/////////////// Transformers ///////////////
public void setCharAt (int i, char c); // Set the character at index i in this string to c.
public void append (String s); // Insert the characters of s after the last character of this string.
public void insert (int i, String s); // Insert the characters of s before the character at index i in // this string.
public void delete (int i, int j); // Delete the characters of this string whose indices are i, …, // j–1.
Question: Tableau ou liste?