question: public int index ( String what ) { if ( what == null ) { for ( int i = 0 ; i < count ; i ++ ) { if ( data [ i ] == null ) { return i ; } } } else { for ( int i = 0 ; i < count ; i ++ ) { if ( what . equals ( data [ i ] ) ) { return i ; } } } return - 1 ; }
target:  Return the first index of a particular value. 