CS 151 - Computer Science I

Fall-2023

Catalog description: First course in Computer Science. Introduces the fundamental concepts of computer programming with an object-oriented language with an emphasis on analysis and design. Topics include data types, selection and iteration, instance variables and methods, arrays, files, and the mechanics of running, testing and debugging.

Prerequisites: MATH 152 (may be taken concurrently)

Course Learning Outcomes:

1. Learn the basic principles of object-oriented programming and the resources available to help them write JAVA programs (editors, JAVA libraries, on-line help manuals, and JAVA development environments).
2. Learn the basic programming constructs, namely primitive data, variables, assignment statement, arithmetic operators, parameter passing.
3. Learn the main control structures, namely Boolean expressions, conditional statements, loops.
4. Understand and implement Java classes and use them in definite application settings. Understand the ideas of abstraction and encapsulation, and incorporate them into program design.
5. Understand and utilize text files and basic input/output operations.
6. Learn arrays of primitive data and arrays of objects.
7. Learn how to interpret non-trivial application problems (problem analysis) and translate them into pseudo-code (program design) before implementing them in JAVA.

Required software: BlueJ - an integrated Java programming environment (http://www.bluej.org/)

Class Participation: All students are expected to attend class sessions regularly. If you must miss a test, try to inform the instructor of this in advance. In case of missed classes and work due to plausible reasons (such as illness or accidents) limitted assistance will be offered. Unexcused absences will result in the student being totally responsible for the make-up process.

Assignments: Reading and problem assignments are listed in the schedule of classes. Some of the problems will be worked in class. Self-review questions, exercises and programming projects under the Assignment section don't have to be turned in, but are recommended.

Tests: There will be 5 quizzes, two tests and a final exam. They will include material from the textbook, the lectures, and the programming projects.

Programming projects: There will be 6 programming projects requiring the use of BlueJ to write and run Java programs. The projects with their due dates are listed below in the schedule of classes (the project descriptions are given in Blackboard). All projects must be submitted through Blackboard.

Honesty policy: The CCSU honor code for Academic Integrity is in effect in this class. It is expected that all students will conduct themselves in an honest manner and NEVER claim work which is not their own. Violating this policy will result in a substantial grade penalty, and may lead to expulsion from the University. You may find it online at http://web.ccsu.edu/academicintegrity/. Please read it carefully.

Grading: The final grade will be based on projects (50%), quizzes (10%), tests (20%), and the final exam (20%), and will be affected by classroom participation, conduct and attendance. All grades will be availabe from Blackboard. The letter grades will be calculated according to the following table:

A	A-	B+	B	B-	C+	C	C-	D+	D	D-	F
95-100	90-94	87-89	84-86	80-83	77-79	74-76	70-73	67-69	64-66	60-63	0-59

Unexcused late submission policy: Projects submitted more than two days after the due date will be graded one letter grade down. Projects submitted more than a week late will receive two letter grades down. No submissions will be accepted more than two weeks after the due date.

Students with disabilities: Students who believe they need course accommodations based on the impact of a disability, medical condition, or emergency should contact me privately to discuss their specific needs. I will need a copy of the accommodation letter from Student Disability Services in order to arrange class accommodations. Contact Student Disability Services, Willard Hall, 101-04 if you are not already registered with them. Student Disability Services maintains the confidential documentation of your disability and assists you in coordinating reasonable accommodations with your faculty.

Schedule of classes, projects and tests (organized by topic, each covered in 1-3 classes)

1. Aug 30, Sep 6: Introduction to computers and programming
• Topics:
• What is Computer Science?
• Computational Thinking: http://www.cs.cmu.edu/~CompThink/, http://www.cs4fn.org/computationalthinking/
• A little history: Who Invented the Computer? Turing Machines, A Turing Machine Applet, John von Neumann, IT History Society
• Von Neumann Architecture,  non-Von Neumann computing (NN, ALVINN)
• Computer Programming
• Representing information in computers, number systems ("there are 10 types of people in this world, those who understand binary and those who don't")
• Lecture slides: Chap01.pptx
• Programs/Exercises: Hello.asm (runs with PCSpim), Hello.java (runs with JDK or BlueJ)
• Assignments:
• Watch The Ghost in the Machine
• Read Sections 1.1 - 1.3, Appendix B
• Answer Self-Review Questions: 1.1, 1.2, 1.4, 1.5-1.8, 1.10-1.12
• Compile and run Hello.java using JDK (javac.exe and java.exe in a command prompt window)
• Download, install and get familiar with BlueJ (http://www.bluej.org/)
2. Sep 11, 13: Java language and Object-Oriented Programming
• Topics:
• Writing and running Java programs
• Comments, identifiers and reserved words
• Program development cycle
• Object-Oriented programming
• Print method, character strings, escape sequences
• Lecture slides: Chap01.pptx
• Programs/Exercises:
• Hello.java
• Print "This is my first Java program" on the next line by adding another print statement,
• or (2) by including the message in the same print statement (escape sequence).
• PlusOperator.java
• Remove the parentheses enclosing the arithmetic addition and explain what happens and why.
• Try other parenthesizings and explain the results.
• Print strings and arithmetic expressions with separate statements.
• Write a program to compute the celsius equivalent of today's temperature (use the formula C=(F-32)*5/9). Use BlueJ to create a new project and a new class, then add the code for the main method.
• Assignments:
• Read Sections 1.4 - 1.6, 2.1
• Run the programs and do the exercises described above
• Answer Self-Review Questions: 1.21-1.26, 1.28-1.32, 2.1-2.8
• Do Exercises: 1.2, 1.3, 1.14, 1.15, 1.17, 1.18, 1.20, 2.3-2.6
• Do Programming Projects: 1.1, 1.2, 1.3
• Sep 14: Take Quiz 1 (Sections 1.1-1.6, 2.1) online in Blackboard
• Sep 18: Submit Programming Project 0
3. Sep 18, 20, 25: Data and Expressions
• Topics:
• Character strings
• Primitive data types. Variables. The assignment statement and arithmetic operators.
• Data conversion
• Interactive programs. The Scanner class.
• Lecture slides: Chap02.pptx
• Programs/Exercises:
• Arithmetic.java (note the difference between integer division and floating point division, explain the modulo operation)
• PrimitiveTypes.java
• Explain the output
• Print the values of the variables (combine them in the string)
• Fix the overflow problem (two's complement representation) with long, float, and double types and explain the difference
• Try 2.147483647E9 instead of 2147483647 and explain what happens and why (narrowing conversion)
• GasMileage.java (Listing 2.9)
• What happens if you enter 20.5 for miles? Fix the problem in two ways.
• What happens if enter miles and gallons on the same line?
• Modify the program so that it reads two lines of inputs with car, miles, and gallons (separated by blanks) and prints mpg for each car.
• Fraction.java (see also  Rational number, Mixed numbers)
• Print the sum of the fractions as a rational number
• Print the sum of the fractions as a mixed number number
• Print the sum of the fractions as a floating point number
• Explain results for a=1, b=100000001, c=1, d=100000002 (underflow)
• Write a program, which asks the user for a change amount in cents and computes and prints the number of quarters, dimes, nickels, and pennies to be returned.
• Assignments:
• Read Chapter 2
• Run the programs and do the exercises described above
• Answer Self-Review Questions: 2.9-2.29, 2.31-2.37
• Do Exercises: 2.7-2.12
• Do Programming Projects: 2.2-2.6
• Sep 28: Take Quiz 2 (data types, assignments, data conversion, interactive programs) online in Blackboard
• Sep 29: Submit Programming Project 1(8 points)
4. Sep 27, Oct 2, 4: Using classes and objects
• Topics
• Creating objects, aliases, wrapper classes
• The Strings class
• The Random class, packages
• The Math class
• Enumerated types
• Lecture slides: Chap03.pptx
• Programs/Exercises:
• StringMutation.java, RandomNumbers.java, Quadratic.java
• Apply mutation4 to the original string (phrase). Explain and fix the error.
• Write a program that reads a string and prints a random substring.
• Write a program that generates a random quadratic equation and prints its roots.
• StringObjects.java
• Write a program to read two strings and print true/false if they are equal/not equal.
• Extend the program with the compareTo method.
• Translate.java (Read a double digit number (20-99) and print it in words, e.g. 35 should print as "thirty-five")
• Objects.java (make the changes and explain the results)
• IceCream.java (Assign chocolate flavor to cone3 and compare it with cone2 using "==" and "equals")
• Digits.java (What happens with a wrong input? Extend the program to read input like "two plus three" and print the result).
• Assignments:
• Read Sections 3.1 - 3.8
• Run the programs and do the exercises described above
• Answer Self-Review Questions: 3.1 - 3.9, 3.16 - 3.21, 3.29 - 3.31, 3.32 - 3.35
• Do Exercises: 3.4, 3.5, 3.7 - 3.10
• Do Programming Projects: 3.1 - 3.5
• Oct 5: Take Quiz 3 (creating objects, aliases, wrapper classes, Strings class, Random class) online in Blackboard
5. Oct 9, 11: Decision making and Loops
• Topics
• Boolean expressions and logical operators
• Comparing data and objects
• Conditionals: the if - else and switch statements
• Loops: the while statement
• Lecture slides: Chap05.pptx
• Programs/Exercises:
• CheckInput.java (change the intervals to open/close, use if-else to read and validate a percentage value)
• Write a program to read and validate a tip percentage and apply it to a given restaurant bill.
• Age.java (add age intervals - kid (<=18), adult (18,65), senior (>=65), add a birthday message)
• See Top 25 Most Dangerous Programming Errors. Add input type and range validation to Age.java
• Calculator.java (replace the if-else-if structure with a switch, note the type of the expression in the switch statement)
• Gcd.java (implement the version based on subtraction)
• Grade.java (add input type verification)
• Write a program to add two rational numbers (see Fraction.java) and simplify the sum using GCD.
• StudentGrades.java (use a sentinel value or a question to the user for the stopping condition, do counting and averaging in grade intervals - excellent (> 89), ok [60,89], and failure (< 60))
• Assignments:
• Read Sections 5.1 - 5.4, 6.1
• Run the programs and do the exercises described above
• Answer Self-Review Questions: 5.1 - 5.23, 6.1 - 6.4
• Do Exercises: 5.2 - 5.5, 5.7 - 5.11
• Do Programming Projects: 5.1 , 5.3, 5.4
• Oct 16: Submit Programming Project 2 (8 points)
6. Oct 16, 18, 23: Loops continued
• Topics
• The do and for statements
• Leading decision (pretest) vs. trailing decision (posttest) loops
• Nested loops
• Lecture slides: Chap06.pptx
• Programs/Exercises:
• PrintDigits.java
• What happens with input 0? Change the while-loop to a do-loop.
• Compute the sum of the digits of an integer.
• Use nested loops to prove experimentally that if the sum of the digits of a number is 9,  then the number is multiple of 9
• Loops.java
• Move the index increment in the beginning of the while and do loops, explain the difference
• Print the squares from 0 to 100 with increments of 5
• Use user specified range and increment
• Print the multiplication table for 9 (or for a user specified number)
• Guess.java
• Change the range of numbers. What is the optimal strategy?
• Include a counter to count the number of guesses
• Change the do-loop with a while-loop
• Series.java
• Change the while-loop to do-loop or for-loop.
• Use an outer loop (nested loops) for n=1,2,4,8,...,2^m to print a table of n and sum
• Use a conditional print (i % 100 == 0) instead of nested loops to print the table (compare efficiency).
• Use powers of 2 in the conditional print (Math.log(i)/Math.log(2) % 2 == 0).
• Find the first n for which sum >= 10.
• Modify the series to 1/2+1/4+1/8+1/16 +... and do the convergence experiments. See Zeno's paradox  and an interactive demo.
• str2int.java (change the for-loop to while-loop, print the position of the wrong input character)
• Pi.java
• Iteration.java
• Divisors.java
• Print the sum of the proper divisors of each number
• For each number print if it is deficient, abundant or perfect (see these links deficient, abundant or perfect).
• Count how many numbers are deficient, abundant and perfect.
• Primes.java (change the for-loop to a while-loop).
• Assignments:
• Read Sections 6.3, 6.4
• Run the programs and do the exercises described above
• Answer the Self-Review Questions after Sections 6.1, 6.3, 6.4
• Do Exercises 6.1 - 6.12
• Do Programming Projects 6.1 - 6.3, 6.7.
• Oct 30: Submit Programming Project 3 (8 points)
7. Oct 25: Test 1 (Chapters 2, 3, 5, 6)
8. Oct 30, Nov 1: Writing classes
• Topics
• Writing user-defined classes and methods
• Encapsulation and visibility modifiers
• Parameters
• Constructors, accessors, mutators
• Instance and local data
• Lecture slides: Chap04.pptx
• Programs/Exercises:
• Die.java, RollingDice.java (pass the initial face value as a parameter of  the constructor, change visibility modifiers to access instance variables directly, roll dice in a loop until their face values are equal, compute probability)
• Account.java, Transactions.java (write a loop to find out after how many years the balance will double, write a method to set the interest rate)
• Assignments:
• Read Sections 4.1 - 4.5
• Answer the Self-Review Questions 4.1 - 4.25
• Do exercises 4.5 - 4.8
• Do Programming Projects 4.1 - 4.4, 4,6, 4.9
• Run the programs and do the exercises described above
9. Nov 6, 8: Java classes continued
• Topics
• Parameter passing
• Static variables and static methods
• Dependencies among classes, and dependencies among objects of the same class
• Lecture slides: Chap07.pptx
• Programs/Exercises:
• Rational.java, AddRationals.java (do the suggested exercises)
• Series1.java (do the suggested exercises)
• Slogan.java, SloganCounter.java
• Static variables/methods: change Slogan.getCount() to obj.getCount(), remove/add static to count and getCount()
• Visibility modifiers: change/remove the visibility modifier of getCount()) and count,
• Encapsulation: replace Slogan.getCount() with Slogan.count
• Instance/local variables: add method setCount(int x), add/remove int in int count=x
• Assignments:
• Read Sections 7.1 - 7.4
• Answer the Self-Review Questions 7.6 - 7.13
• Do exercises 7.1, 7.4, 7.11
• Do Programming Projects 7.1, 7.2
• Run the programs and do the exercises described above
• Nov 9: Take Quiz 4 (Chapters 4 and 7) online in Blackboard
• Nov 13: Submit Programming Project 4 (8 points)
10. Nov 13: Still more Java classes
• Topics
• The this reference
• Method parameters
• Method overloading
• Lecture slides: Chap07.pptx
• Programs/Exercises:
• Max.java, Scope.java, Num.java (modify setValue(int value) and use the "this" reference, add static to instance variable value)
• Num.java, ParameterModifier.java, ParameterTester.java
• try to add static to setValue() in class Num
• add static to value in class Num and explain the output
• add Num next; and another constructor Num(value, next) to class Num
• create a chain (list) of numbers: Num a = new Num(0); a = new Num(1,a); a = new Num(2,a);
• write a loop to print all numbers along the chain
• use a loop to create a list of numbers: Num x=null; for (int i=1;i<=10;i++) x = new Num(i,x);
• Review of Test 2 (Chapters 4 and 7)
• Assignments:
• Read Sections 7.7, 7.8
• Run the programs and do the exercises described above
• Do exercises 7.2, 7.3, 7.5
11. Nov 15: Test 2 (Chapters 4 and 7)
12. Nov 20: Working with text files
• Topics
• Text files
• Iterators
• Lecture slides: Chap05.pptx
• Programs/Exercises:
• URLDissector.java, urls.txt (print the server name only, print the file name only, count the URLs, compute the average number of components)
• Student.java, Students.java (do the suggested exercises), students.txt
• Assignments:
• Read Sections 5.5
• Answer the Self-Review Questions 5.24, 5.25
• Do Programming Projects 5.13 - 5.15
• Run the programs and do the exercises described above
• Nov 29: Submit Programming Project 5 (8 points)
13. Nov 27, 29: Arrays
• Topics.
• Array elements
• Declaring and using arrays of primitive data types
• Passing arrays as parameters
• Lecture slides: Chap08.pptx
• Programs/Exercises:
• ReverseOrder.java (ask the user for the number of elements, define a method for printing the array in reverse order, define a method that returns an array)
• LetterCount.java
• array.java (create a method to print the array and use it to trace finding of min/max and sorting). For bubble sort see: http://www.youtube.com/watch?v=lyZQPjUT5B4?feature=youtu.be and http://www.youtube.com/watch?v=k4RRi_ntQc8
• StringToArray.java (comparing arrays of char and strings)
• Assignments:
• Read Sections 8.1, 8.2
• Answer the Self-Review Questions 8.1 - 8.13
• Do Exercises 8.1, 8.4, 8.6 - 8.10
• Do Programming Projects 8.1, 8.3, 8.5
• Run the programs and do the exercises described above
• Nov 30: Take Quiz 5 online in Blackboard for 2 points + 5 points extra credit
14. Dec 4, 6: Arrays of objects
• Topics
• Arrays of objects
• Two-dimensional arrays
• Command-line arguments
• Lecture slides: Chap08.pptx
• Programs/Exercises:
• index.java (create methods for converting a digit into word and vice versa).
• Use command-line arguments for the user input in index.java.
• Using two-dimensional arrays write methods for printing a matrix of integers and for transposing a matrix.
• Implement Students.java using an array of objects of class Student.java (implement a method for printing students and methods for finding/printing students by name or grade)
• Assignments:
• Read Sections 8.3 - 8.4, 8.6
• Answer the Self-Review Questions 8.14 - 8.19
• Do Exercise 8.5
• Do Programming Project 8.6
• Run the programs and do the exercises described above
• Dec 11: Submit Programming Project 6 (10 points)
15. December 13, 1:00pm - 3:00pm: Final Exam (see Review topics and sample problems)

Programming Project 0

Programming Project 1

Programming Project 2

Programming Project 3

Programming Project 4

Programming Project 5

Programming Project 6

Test 1 Review Topics

• Boolean expressions and logical operators
• Type conversions, casting
• Comparing data
• If statement and conditions. Pay special attention to the syntax (the use of ;) and to the else clause
• Switch statement
• While (leading decision) loops
• Do (trailing decision) loops
• For loops
• Rewriting code with different loops
• Writing programs with simple loops

• Exercises: 5.2 - 5.5, 5.7 - 5.11
• Exercises: 6.1 - 6.8
• Print the conversion table of miles to kilometers from 0 to 100 with increments of 5. Print miles as integers and kilometers as doubles.
• Use user specified range and increment
• Print the multiplication table for 9 (or for a user specified number)

Test 2 Review Topics

• Class structure (instance data, methods), creating and using objects.
• Primitive data, objects, references to objects (note that Strings are objects).
• Encapsulation and visibility modifiers.
• Types of methods (constructors, accessors, mutators).
• Method parameters, local variables.
• Static methods and static variables.
• Method signature and method overloading.

• EX 4.5 - EX 4.8 (page 185)
• Write a class called Wallet. It has four instance variables singles, fives, tens, and twenties (all int type). The class has one constructor (which has a parameter corresponding to each instance variable), getter and setter methods for each instance variable, and two service methods: totalMoney, which returns the total dollar amount in the wallet, and getMoney, which takes a dollar amount as a parameter and updates the number of singles, fives, tens and twenties in the wallet. Write an application class that contains the main method. In the main method create two Wallet objects, and use the getter and setter method to transfer $30 from one of the wallets to the other. Print the total amount of money in each wallet before and after the transfer. Solution (extended): Wallet.java, WalletRunner.java

Final Exam Review Topics

• Variables types, arithmetic expressions, casting
• If statements: condition, "else" and "else if" clauses.
• Loops: for-loops, while-loops, do-loops, nested loops
• Primitive data and objects: comparing, passing as parameters
• Arrays: declaration, initialization, indexing, passing arrays as parameters (note that arrays are objects), finding min/max element, arrays of objects
• Using classes: creating objects, object reference variables
• Creating classes: instance data and methods (visibility modifiers, encapsulation, static/non-static), parameters, local variables, "this" reference

Example Problem 1: You deposit $2000 in a bank that provides 1.5% monthly interest rate. At the end of each month after applying the interest you withdraw $150. Write a program that prints a table showing your balance at the end of each month for 12 months. Solution: Bank.java

Example Problem 2: Write a method that takes an array of integers as a parameter and computes and prints the sum of the squares of its elements. Solution: IntArray.java

Example Problem 3: Write a class called Employee that contains three instance variables representing employee s first name (String type), last name (String type) and salary (int type), a constructor assigning values to these variables, getter and setter methods for the salary, and a toString() method that returns the employee information. Write another class containing the main method that declares an array of objects of class Employee with 10 elements. Initialize each element with an Employee object created with data entered from the keyboard by using the Scanner class and print the array. Then find the employee with the minimal salary and increase it with 10%. Print the employee information before and after the pay raise. Solution: Employee.java, Company.java