question: public final int indexOf ( char c , int fromIndex ) { if ( ( _offset + fromIndex ) >= ( _offset + _length ) ) throw new IndexOutOfBoundsException ( String . format ( "From Index %d Is Out of Bounds" , fromIndex ) ) ; for ( int i = _offset + fromIndex , end = _offset + _length ; i < end ; i ++ ) { if ( _array [ i ] == c ) return i - _offset ; } return - 1 ; }
target:  Returns the index within this character sequence of the first occurrence of the specified character searching forward, starting from the specified index.