38: Exam#1: Written , Name: ___________________________

• CS 340, Fall 2019, York College of Pennsylvania
• 41, 150 points, 2019-10-10 (at start of class)

On the left half of the page, write the numbers from 0 to 15, one per line. Do this in binary (left most column), hexadecimal (middle column), and decimal (rightmost column). Include the appropriate suffix for each number.

You will be given a decimal number in the range of 0 to 255. On the right part of the page, convert that number to base 2 and base 16 representation, including the appropriate suffix for each number. Clearly indicate each answer by drawing a box around just the answer for each part.

• Number: (omitted)

You will be provided a logical expression.

For the logical expression provided, construct an extended truth table, as done in class and as appears in the notes. Above the extended truth table, draw a tree for the logical expression, as done in class. Order the possible values for the variables in the expression as done in class using a binary ordering.

• The tree must be above the extended truth table and all nodes should be lined up with the corresponding operator or operand.

Add a label (variable name) for each operator node, starting with a and the left and continuing to the right.

Below the extended truth table, write the assignment statements, using the variable name labels for the operators, that, given values for the logical variables, will calculate the values of all interior nodes.

Pick any 3 different programming languages.

Language 1:
Language 2:
Language 3:

Write a program in language 1 that writes a program in language 2 that writes a program in language 3 that outputs the text "CS340".

• Show the text of language 3: (last)
• Show the text of language 2: (that writes language 3)
• Show the text of language 1: (that writes language 2 that writes language 3)

Use the provided postfix code and values for the variables in the postfix code.

• The first line should be "init the stack".
• Write the variable or operator, left justified on a separate line.
• On the following line(s) for each variable or operator, write the actions(s), for that variable or operator.
• pushes should have the form "push expression as value".
• pops should have the form "pop value as variable".
• Use reg1 and reg2 as temporary registers.
• The last line should indicate the result.

The variable values to be used will be provided. (Note: This was done in class when the exam was given and this text added after the exam).

Postfix code list: omitted
Variable values: (omitted)

Given a tree in prefix form and only containing variables and the NAND "!&" binary operator, write a tree traversal routine in a programming language of your choice (except JavaScript) to do an output or transformation which will be one of the following.

• output a prefix representation
• output an infix representation
• output a postfix representation

Note: The tree traversal code should be based on the JavaScript tree traversal code covered in class (and in the notes), except that this problem is simplified in that both integer literals and unary operators are omitted in this problem.

During class time, we covered the background and history of the following programming languages.

Pick language#1 from the following group.

C, C++, Java, Pascal

Pick language#2 from the following group.

JavaScript, Lua, PHP, Python

Write a short essay of no more than one page as follows.

First paragraph/sentence: Identify the two languages picked and that you are comparing.

For each of the two languages, write a short paragraph that contains the following. The creator of the language, the time frame it was created, some of the goals of that language, and some good points and some bad points of that language.

Last paragraph/sentence: Write a summary of what you have discussed.