comefrom: <qiyuangong>709_To_Lower_Case_2.java
code: public String toLowerCase(String str) {
          char[] a = str.toCharArray();
          for (int i = 0; i < a.length; i++)
              if ('A' <= a[i] && a[i] <= 'Z')
                  a[i] = (char) (a[i] - 'A' + 'a');
          return new String(a);
      }
masked: public String var_0 ( String var_2 ) {
    char [ ] var_4 = var_2 . toCharArray ( ) ;
    for ( int var_6 = 0 ;
    var_6 < var_4 . length ;
    var_6 ++ ) if ( 'A' <= var_4 [ var_6 ] && var_4 [ var_6 ] <= 'Z' ) var_4 [ var_6 ] = ( char ) ( var_4 [ var_6 ] - 'A' + 'a' ) ;
    return new String ( var_4 ) ;
  }
  