Starting Computing Homework 4

All 4 components (Cloud9 workspace, Moodle CodeRunner attempts, multiple choice questions, and zip file) must be completed and submitted by Saturday, February 9th, 6:00 pm for your homework to receive points.



                    1. Objectives


    • Understand and work with if­else conditionals and switch statements.

    • Writing and testing C++ functions

        ◦ Understand problem description

        ◦ Design your function:

            ▪ come up with a step by step algorithm,

            ▪ convert the algorithm to pseudocode

            ▪ imagine many possible scenarios and corresponding sample runs or outputs

        ◦ Convert the pseudocode into a program written in the C++ programming language

        ◦ Test it in the Cloud9 IDE and submit it for grading on Moodle




                2. Background



Conditional Statements

Conditional statements in computer science are features of a programming language which execute different computations or actions based on the outcome of a boolean condition. Boolean conditions are expressions that evaluate a relationship between two values and then return either True or False. Conditionals are mostly used in order to alter the control flow, or the order in which individual instructions are carried out, of a program.







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Largely, conditional statements fall into two types:

    1. If­else statements, which execute one set of statements or another based on the value of a given condition
    2. Switch statements, which are used for exact value matching and allow for


multi­way branching

IF­ELSE statements:

The if statement selects and executes the statement(s) based on a given condition. If the condition evaluates to True then a given set of statement(s) is executed. However, if the condition evaluates to False, then the given set of statements is skipped and the program control passes to the statement following the if statement. If we have another else statement next to this, it is handled by the else block.

The general syntax of the if­else statement is as follows:















































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Nested IF­ELSE:

If there are more than 2 branches within your program, we can use nested if statements to model this behavior within a program by putting one if statement within another. Below is an example of the syntax of a nested if statement.






























SWITCH statements:

Switch case statements are a substitute for long if statements that compare a variable to several integral values.

    • The switch statement is a multiway branch statement. It provides an easy way to dispatch execution to different parts of code based on the value of the expression


●    Switch is a control statement that allows a value to change control of execution.














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Syntax:

With the switch statement, the variable name is used once in the opening line. A case keyword is used to provide the possible values of the variable, which is followed by a colon and a set of statements to run if the variable is equal to a corresponding value.


switch (n){

case 1:

    • code to be executed if n = 1; break;

case 2:

    • code to be executed if n = 2; break;

default:

// code to be executed if n doesn’t match any cases

}


Important notes to keep in mind while using switch statements :

1.    The expression provided in the switch should result in a constant value otherwise it would not be valid.


a.    switch(num) //allowed (num is an integer variable)


b.    switch(‘a’) //allowed (takes the ASCII Value)


c.    switch(a+b) //allowed,where a and b are int variable, which are defined
earlier


2.    Duplicate case values are not allowed.


3.    The  break statement  is  used  inside  the  switch  to  terminate  a  statement sequence. When a break statement is reached, the switch terminates, and the
flow of control jumps to the next line following the switch statement.


4.    The default statement is optional. Even if the switch case statement do not have
a default statement,it would run without any problem.


5.    Nesting  of  switch statements are allowed, which means you can have switch statements inside another switch. However nested switch statements should be
avoided as it makes program more complex and less readable.


6.    The break statement is optional. If omitted, execution will continue on into the next case. The flow of control will fall through to subsequent cases until a break
is reached.














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Relational Operators:

A relational operator is a feature of a programming language that tests or defines some kind of relation between two entities. These include numerical equality (e.g., 5 = 5) and inequalities (e.g., 4 ≥ 3). Relational operators will evaluate to either True or False based on whether the relation between the two operands holds or not. When two variables or values are compared using a relational operator, the resulting expression is an example of a boolean condition that can be used to create branches in the execution of the program. Below is a table with each relational operator’s C++ symbol, definition, and an example of its execution.

>
greater than
5 > 4 is TRUE



<
less than
4 < 5 is TRUE



>=
greater than or equal
4 >= 4 is TRUE



<=
less than or equal
3 <= 4 is TRUE



==
equal to
5 == 5 is TRUE



!=
not equal to
5 != 4 is TRUE




Logical Operators

Logical operators are symbols that are used to compare the results of two or more conditional statements, allowing you to combine relational operators to create more complex comparisons. Similar to relational operators, logical operators will evaluate to True or False based on whether the given rule holds for the operands. Below are some examples of logical operators and their definitions.

●    && (AND) returns true if and only if both operands are true


●    || (OR) returns true if one or both operands are true


●    ! (NOT) returns true if operand is false and false if operand is true






Truth Tables

Every logical operator will have a corresponding truth table, which specifies the output that will be produced by that operator on any given set of valid inputs. Below are examples of truth tables for each of the logical operators specified above.





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AND:

These operators return true if and only if both operands are True. This can be visualized as a venn diagram where the circles are overlapping.


p
q
p && q
True
True
True



True
False
False



False
True
False



False
False
False






OR:

These operators return True if one or both of the operands are True. This can be visualized as the region of a venn diagram encapsulated by both circles.


p
q
p || q
True
True
True



True
False
True



False
True
True



False
False
False




NOR:

These operators return True if both of the operands are False. This can be visualized as the region of a venn diagram that is not within either of the circles.


p
q
!(p || q)
True
True
False



True
False
False



False
True
False



False
False
True









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3. Submission Requirements


All three steps must be fully completed by the submission deadline for your homework to be graded.

    1. Share your Cloud 9 workspace with your TA(if you have not done yet): Your recitation TA will review your code by going to your Cloud9 workspace. TAs will check the last version that was saved before the submission deadline.

        ◦ Create a directory called Hmwk4 and place all your file(s) for this assignment in this directory.

        ◦ Share your workspace by clicking Share in the upper right hand corner and inviting your TA using their Cloud9 username.

        ◦ Make sure to save the final version of your code (File > Save). Verify that this version displays correctly by going to File > File Version History.

        ◦ The file(s) should have all of your functions, test cases for the functions in main() function(s), and adhere to the style guide. Please read the Test Cases and Style and Comments sections for more details.

    2. Submit to the Moodle CodeRunner: Head over to Moodle to the link Homework 4 CodeRunner. You will find one programming quiz question for each problem in the assignment. Submit your solution for the first problem and press the Check button. You will see a report on how your solution passed the tests, and the resulting score for the first problem. You can modify your code and re­submit (press Check again) as many times as you need to, up until the assignment due date. Continue with the rest of the problems.

    3. Complete Multiple Choice Questions: There are 4 Multiple Choice Questions (MCQs) which refer to problem 5, countDigits. You can find Homework 4 MCQ Quiz on Moodle. You can attempt at most 2 times, and you have 20 minutes for each attempt to answer 4 questions. Your highest grade will be count toward your Homework 4 grade.

    4. Submit a .zip file to Moodle: After you have completed all 7 questions from the Moodle assignment, zip all 7 solution files you compiled in Cloud9 (one cpp file for each problem), and submit the zip file through the Homework 4 (File Submission) link on Moodle.





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TA Name
Cloud 9 username
TA Name
Cloud 9 username




Shipra Behera
beherashipra
Telly Umada
TetsumichiUmada




Josh Ladd
joshladd
Ashwin
ashwinsankaralingam


Sankaralingam





Chu­Sheng Ku
chusheng
Supriya Naidu
supriyanaidu




Punith Patil
variable314
Sebastian
slaudens


Laudenschlager





Karthik Palavalli
karthikpalavalli
Dhanendra Soni
dhanendra




Thanika Reddy
thanika
Shudong Hao
shudonghao











4. Rubric


Aside from the points received from the Homework 4 CodeRunner quiz problems, your TA will look at your solution files (zipped together) as submitted through the Homework 4 (File Submission) link on Moodle and assign points for the following:

Comments (5 points):

    • Your code should be well­commented. Use comments to explain what you are doing, especially if you have a complex section of code. These comments are intended to help other developers understand how your code works. These comments should begin with two backslashes (//) or the multi­line comments (/*

        ◦ comments here… */) .

    • Please also include a comment at the top of your solution with the following format:

            ▪ CS1300 Spring 2019

            ▪ Author: my name

            ▪ Recitation: 123 – Favorite TA

            ▪ Cloud9 Workspace Editor Link: https://ide.c9.io/…

            ▪ Homework 4 - Problem # ...











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Algorithm (5 points):

    • Before each function that you define, you should include a comment that describes the inputs and outputs of your function and what algorithms you are using inside the function.

    • This is an example C++ solution. Look at the code and the algorithm description for an example of what is expected.

Example 1:


/*

    • Algorithm: convert money from U.S. Dollars (USD) to Euros.

    • 1. Take the value of number of dollars involved in the transaction.

    • 2. Current value of 1 USD is equal to 0.86 euros

    • 3. Multiply the number of dollars got with the currency

    • exchange rate to get Euros value

    • 4. Return the computed Euro value

    • Input parameters: Amount in USD (double)

    • Output (prints to screen): nothing

    • Returns: Amount in Euros (double)

*/



Example 2:


double convertUSDtoEuros(double dollars)

{

double exchange_rate = 0.86; //declaration of exchange rate double euros = dollars * exchange_rate; //conversion return euros; //return the value in euros

}

The algorithm described below does not mention in detail what the algorithm does and does not mention what value the function returns. Also, the solution is not commented. This would work properly, but would not receive full credit due to the lack of documentation.


/*

    • conversion

*/

double convertUSDtoEuros(double dollars)

{

double euros = dollars * 0.86;

return euros;

}











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Test Cases (20 points):

    1. Code compiles and runs (6 points):

        ◦ The zip file you submit to Moodle should contain 7 full programs (each with a main() function), saved as .cpp files. It is important that your programs can be compiled and run on Cloud9 with no errors. The functions included in these programs should match those submitted to the CodeRunner on Moodle.

    2. Test cases (14 points):

For this week’s homework, all 7 problems are asking you to create a function. In your Cloud9 solution file for each function, you should have 2 test cases present in their respective main() function, for a total of 14 test cases (see the diagram on the next page). Your test cases should follow the guidelines, Writing Test Cases, posted on Moodle under Week 3.















































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5. Problem Set


Note: To stay on track for the week, we recommend to finish/make considerable progress on problems 1­3 by Wednesday. Students with recitation on Thursday are encouraged to come to recitation with questions and have made a start on all of the problems.




Problem 1 (5 points): numberSign

Write a function named numberSign that takes one integer parameter, returns nothing, and prints to the screen whether that integer is "negative", "positive", or "zero".

    • Your function MUST be named numberSign

    • Your function takes one input argument: an integer number

    • Your function should not return any value

    • Your function prints/outputs to the console window a message, as specified above

Examples:

    • When the argument is equal to 4, the function should print positive;

    • When the argument is equal to ‑4, the function should print negative;

    • When the argument is equal to 0, the function should print zero.

In Cloud9 the file should be called numberSign.cpp and it will be one of 7 files you need to zip together for the Homework 4 (File Submission) on Moodle.

Don’t forget to head over to Moodle to the link Homework 4 CodeRunner. For Problem 1, in the Answer Box, paste only your function definition, not the entire program. Press the Check button. You can modify your code and re­submit (press Check again) as many times as you need to.



Problem 2 (5 points): collatzStep

Write a function collatzStep which takes a single integer argument and returns an integer. The return value should be the next value in the Collatz sequence based on the value of the input parameter. If the given value n is even, the next value should be n/2 . If n is odd, the next value should be 3n+1 . If the given value is not positive the function should return 0.




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    • Your function MUST be named collatzStep

    • Your function takes one input argument: an integer number

    • Your function must return an integer, as specified above

Examples:

    • When the argument is equal to 4, the function should return 2;

    • When the argument is equal to 7, the function should return 22;

    • When the argument is equal to ‑5, the function should return 0.

In Cloud9 the file should be called collatzStep.cpp and it will be one of 7 files you need to zip together for the Homework 4 (File Submission) on Moodle.

Don’t forget to head over to Moodle to the link Homework 4 CodeRunner. For Problem 2, in the Answer Box, paste only your function definition, not the entire program. Press the Check button. You can modify your code and re­submit (press Check again) as many times as you need to.



Problem 3 (10 points): checkEqual

Write a function checkEqual which takes three numbers as parameters, and prints

    • “All same”, if they are all the same

    • “All different”, if they are all different

    • “Neither”, otherwise

    • Your function MUST be named checkEqual

    • Your function takes three input arguments: all integers

    • Your function must print one of the above three statements

    • Your function should NOT return anything

Examples:

    • If the input arguments are (1, 2, 3), the function should print All different

    • If the input arguments are (2, 2, 2), the function should print All same

    • If the input arguments are (1, 1, 2), the function should print Neither

In Cloud9 the file should be called checkEqual.cpp and it will be one of 7 files you need to zip together for the Homework 4 (File Submission) on Moodle.







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Don’t forget to head over to Moodle to the link Homework 4 CodeRunner. For Problem 3, in the Answer Box, paste only your function definition, not the entire program. Press the Check button. You can modify your code and re­submit (press Check again) as many times as you need to.



Problem 4 (10 points): chessBoard

Each square on a chess board can be described by a letter and number, such as g5 in this example.





















Write a function chessBoard which determines if a square with a given letter or number on a chessboard, is dark (black) or light (white).

    • Your function MUST be named chessBoard

    • Your function takes two input arguments: a character, and an integer

    • If your function receives as input a valid character and number, then it must print either “black” or “white”, depending on the color of the square given by those coordinates. (Note: the darker squares on the example board above should be considered as black and the lighter squares should be considered as white; non­white/black is used to distinguish between text, pieces and squares.)

    • If your function receives as input anything other than a­h for character, and 1­8 for number, then it must print “Chessboard squares can only have letters between a­h and numbers between 1­8.” Note that your function should discern between the valid lowercase letters and the invalid uppercase ones.

    • Your function should NOT return anything.








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Examples:

    • If the input arguments are (‘g’, 5), the function should print black

    • If the input arguments are (‘c’, 4), the function should print white

    • If the input arguments are (‘a’, 1), the function should print black

    • If the input arguments are (‘A’, 10), the function should print Chessboard squares can only have letters between a‑h and numbers between 1‑8

In Cloud9 the file should be called chessBoard.cpp and it will be one of 7 files you need to zip together for the Homework 4 (File Submission)on Moodle.

Don’t forget to head over to Moodle to the link Homework 4 CodeRunner. For Problem 4, in the Answer Box, paste only your function definition, not the entire program. Press the Check button. You can modify your code and re­submit (press Check again) as many times as you need to.

Problem 5 (10 points): countDigits

Write a function countDigits that takes integer as input and returns how many digits the number has. Assume that all integers are less than 1000 and greater than ­1000. Suggestion: if the number is negative, you could first multiply it with –1.

    • Your function MUST be named countDigits

    • Your function takes one input argument: an integer number

    • Your function must return the number of digits as an integer

Examples:

    • If the argument is equal to 123, the function should return 3;

    • If the argument is equal to ‑75, the function should return 2.

In Cloud9 the file should be called countDigits.cpp and it will be one of 7 files you need to zip together for the Homework 4 (File Submission) on Moodle.

Don’t forget to head over to Moodle to the link Homework 4 CodeRunner. For Problem 5, in the Answer Box, paste only your function definition, not the entire program. Press the Check button. You can modify your code and re­submit (press Check again) as many times as you need to.

Note also that there are 4 Multiple Choice Questions (MCQs) which refer to this problem. You can find Homework 4 MCQ Quiz on Moodle.





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Problem 6 (15 points): countHours

Write a function countHours that takes in a month and returns the number of hours present in the month.

    • Your function MUST be named countHours.

    • Your function takes one input argument: month as integer. For example, January is 1, February is 2 and so on, up to December is 12.

    • Your function should not print anything.

    • Your function should return the number of hours: an integer value.

    • Use switch to solve this problem. if­else is not available.

Note: For this problem we assume all inputs fall in the category of a non leap year, i.e., February has only 28 days.

Examples:

    • When the argument is equal to 1, the function should return 744;

    • When the argument is equal to 2, the function should return 672;

    • When the argument is equal to 4, the function should return 720.

In Cloud9 the file should be called countHours.cpp and it will be one of 7 files you need to zip together for the Homework 4 (File Submission) on Moodle.

Don’t forget to head over to Moodle to the link Homework 4 CodeRunner. For Problem 6, in the Answer Box, paste only your function definition, not the entire program. Press the Check button. You can modify your code and re­submit (press Check again) as many times as you need to.



Problem 7 (15 points): checkLeapYear

Write a function called checkLeapYear that takes a single integer argument representing a year and returns true if it is a leap year and false otherwise. This function should use a single if statement and Boolean operators.

    • Your function MUST be named checkLeapYear

    • Your function takes one input argument: an integer number

    • Your function only uses if. else cannot be used to solve this problem.

    • Your function should return a boolean value, true or false, according to the leap year definition (see below).





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Here is an important question: What is a leap year? In general, years divisible by 4 are leap years. For dates after 1582, however, there is a Gregorian correction: years that are divisible by 100 are not leap years but years divisible by 400 are. So, for instance, 1900 was not a leap year but 2000 was.

Examples:

    • When the argument is equal to 1900, the function should return false;

    • When the argument is equal to 2000, the function should return true.

Note: when you print a boolean variable with the value true, it will display as 1, while false will display as 0.

In Cloud9 the file should be called checkLeapYear.cpp and it will be one of 7 files you need to zip together for the Homework 4 (File Submission) on Moodle.

Don’t forget to head over to Moodle to the link Homework 4 CodeRunner. For Problem 7, in the Answer Box, paste only your function definition, not the entire program. Press the Check button. You can modify your code and re­submit (press Check again) as many times as you need to.

Extra Credit Problem (20 points): integerToRoman

One of the manys ways to represent a number is by using the Roman Numerals system. The system goes as follows

1.    Has seven digits

Roman
Integer Value
Digit



I
1


V
5


X
10


L
50


C
100


D
500


M
1000







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    2. Numbers are formatted accordingly:

        a. Only numbers up to 3,999 are represented.

        b. As in the decimal system, the thousands, hundreds, tens, and ones are expressed separately.

        c. The numbers 1 to 9 are expressed as:























Note that 4 is represented as IV and 9 is represented as IX.



    • Your function MUST be named integerToRoman

    • Your function takes one input argument: an integer number

    • Your function should print(cout) the Roman numeral, with appropriate capitalization

    • Your function should not return any value

Examples:

    • If the input argument is 104, the function should print CIV

    • If the input argument is 490, the function should print CDXC

    • If the input argument is 3999, the function should print MMMCMXCIX



Your mission, should you choose to accept it, is to write a function integerToRoman which takes an integer argument and print its Roman equivalent.

In Cloud9 the file should be called integerToRoman.cpp and submit it to the Homework 4 ­­ Extra Credit Problem (File Submission) on Moodle (submit cpp file, not a zip file).





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Don’t forget to head over to Moodle to the link Homework 4 CodeRunner Quiz ­­ Extra Credit Problem. For this extra credit problem, in the Answer Box, paste only your function definition, not the entire program. Press the Check button. You can modify your code and re­submit (press Check again) as many times as you need to.

6. Homework 4 checklist


Here is a checklist for submitting the assignment:

    1. Complete the code Homework 4 CodeRunner

    2. Complete Homework 4 MCQ Quiz

    3. Submit one zip file to Homework 4 (File Submission). The zip file should be named,

<firstName>_<lastName>_homework4.zip. It should have following 7 files:

        ◦ numberSign.cpp

        ◦ collatzStep.cpp

        ◦ checkEqual.cpp

        ◦ chessBoard.cpp

        ◦ countDigits.cpp

        ◦ countHours.cpp

        ◦ checkLeapYear.cpp

    4. If you work on the extra credit problem (integerToRoman), submit your solution to Homework 4 ­­ Extra Credit Problem (File Submission) and integerToRoman.cpp to Homework 4 ­­ Extra Credit Problem (File Submission) on Moodle (cpp file, not a zip file).

Note: You can earn early submission bonus points (5%) by submitting a zip file with 7 cpp files to Homework 4 (File Submission) by Friday, February 8th, 11:59 pm. Extra credit problem does not affect your early submission bonus points.






















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7. Homework 4 point summary




Criteria



Pts

CodeRunner (problem 1 ­ 7)

Multiple Choice Questions

Comments

Algorithms

Test cases

Recitation attendance (Feb 5 or Feb 7)* Total

5% early submission bonus

Extra credit question

70

20

5

5

20

­30

120

+5%

+20


    • if your attendance is not recorded, you will lose points. Make sure your attendance is recorded on Moodle.
































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