fn most_frequent_character(&self) -> Option<char> {
            // compare by the frequency (value) in the descending order (i.e. the most frequent
            // first), hence "b cmp a".
            self.first_char_sort_by_freq(|a, b| b.cmp(&a))
        }
/// Returns the character having the maximum frequency.
///
/// If many characters are tied for the maximum frequency, the return value is one of them
/// choosen arbitrarily. If self is empty, return `None`.
Returns the character having the maximum frequency.
If many characters are tied for the maximum frequency, the return value is one of them
choosen arbitrarily. If self is empty, return `None`.
Returns the character having the maximum frequency . If many characters are tied for the maximum frequency the return value is one of them choosen arbitrarily . If self is empty return ` None ` .
fn most_frequent_character(&self) -> Option<char> {
            // compare by the frequency (value) in the descending order (i.e. the most frequent
            // first), hence "b cmp a".
            self.first_char_sort_by_freq(|a, b| b.cmp(&a))
        }
fn most_frequent_character ( & self ) -> Option < char > { // compare by the frequency (value) in the descending order (i.e. the most frequent // first), hence "b cmp a". self . first_char_sort_by_freq ( | a , b | b . cmp ( & a ) ) }
Returns the character having the maximum frequency.
Returns the character having the maximum frequency .
&self
&self