Homework 1 – August 30^th - KEY

1. Create a syntactically correct program in mini-language Core using the handout from class. Program must be typed. You may work individually or as a team of two (2) people. Your name(s) must be at the top of the page along with “Assignment #1 – August 30^th”. The printout MUST be turned in at the start of Thursday’s class or it can not be accepted.

Many different possibilities

Simplest:

program

A : integer;

begin

output A;

end;

Some remarks about the program:

• you wrote a program in mini-language Core not in BNF
• you were asked to type the assignment
• you were asked to have Assignment #1 – August 30^th up top
• does it make sense to have a program with no output?

Some errors in work turned in

• correct form of declaration required some identifier : integer;
• assignment, input and output statements required semi-colon as terminator
• the relational operators for less than or equal to and greater than or equal to do not exist
• the only case allowed for identifiers is upper case
• identifiers can not contain digits
• all non-terminals (“things” in angle braces) need to be replaced by terminals
• correct assignment operators is :=
• end if not endif
• there is no way to comment in this language
• assignment statements can only occur after the begin
• ::= and | are meta-symbols and indicating replacement or alternation
• variables should be declared – certainly implied
• if statement requires parentheses around comparison
• while statement requires word loop after condition
• programs are not named (i.e. don’t have identifiers following word program)

if (x = y) then

output x, y;

else

if (x < y) then

output x;

2. Buy the book and bring it to class - The text is Concepts of Programming Languages by Robert W. Sebesta. You may buy either the seventh edition (which is what the bookstore has) or the previous edition (6^th edition) which you may be able to get used.

3. Download the Force 2.0.8 compiler from the web. You can locate it by going keying Force 2.0 into Google and selecting the item Force – Reviews and free downloads at Download.com . The URL is www.download.com/Force/3000-2069_4-10233344.html