1.  difference between:

     x = 3

    and 

     x == 3

2.  difference between:

       scores[index] 

    and

       index


3.  int x=10;
    x + 3;   
    // print x

    ---------------------

    int x=10, y=20;
    x + y;   
    // print x , y


4.  missing matching { }

    for (...) 
      {
        ...
      }

    suggestion: type a pair of { } before adding instructions
                in the body of "for"


5.  semicolon after for(...) and if(...)


    for (...);   <- there should be NO semicolon at the end of this line
      {
        ...
      }

    if (...);    <- there should be NO semicolon at the end of this line
      {
        ...
      }

    That is NOT the end of the instruction--"for" and "if" must
    be followed by the body (instructions) of "for" and "if"


    Similar to:

    area = pi * radius *     <- no semicolon at the end of this line
           radius; 


6.  int x; 
    x = y + 10;

    not declaring a variable before using it



7.  parentheses () 
    curly braces {}
    square brackets []

    are different, but they could look similar on the screen


8.  x == y == z

      vs.

    x + y + z


    Let's take a closer look:

    (x == y) == z   <- what does this mean?

    (x + y) + z     <- what does this mean?


    In math you can say: x = y = z, but this is a statement, 
    which states all three variables have the same value


9.  equality with Strings

    String word1, word2;

    if ( word1 == word2 ) ...

    if ( word1.equals(word2) ) ...