Difference between revisions of "CISC181 S2017 Lab1"

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<p style="font-size:40px">[http://nameless.cis.udel.edu/class_data/181_s2017/Lab1_TestCases.pdf Lab #1 tests]</p>
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* [http://developer.android.com/sdk/index.html Download Android Studio] and install it on your machine
 
* [http://developer.android.com/sdk/index.html Download Android Studio] and install it on your machine
 
<!--
 
<!--
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** Make a new project following [[CISC181_S2017_NewAndroidStudioProject | these ]] instructions
 
** Make a new project following [[CISC181_S2017_NewAndroidStudioProject | these ]] instructions
 
** Confirm that you can build and run it (by pressing the green triangle button or choosing "Run" from the Run menu)
 
** Confirm that you can build and run it (by pressing the green triangle button or choosing "Run" from the Run menu)
** As explained in the subsections below, modify <tt>static void main()</tt>  and create '''two''' other methods in <tt>Lab2</tt>: <tt>static void heronsFormula() { ... }</tt> and <tt>static void convertSeconds() { ... }</tt>  
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** Add your name and section number in a comment before the class declaration
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** As explained in the subsections below, modify <tt>static void main()</tt>  and create '''two''' other methods: <tt>static void heronsFormula() { ... }</tt> and <tt>static void convertSeconds() { ... }</tt>  
 
* Submit your <tt>MyClass.java</tt> on Sakai by '''Friday, February 17'''
 
* Submit your <tt>MyClass.java</tt> on Sakai by '''Friday, February 17'''
  
 
Use proper [https://google.github.io/styleguide/javaguide.html naming and formatting style] throughout your code.
 
Use proper [https://google.github.io/styleguide/javaguide.html naming and formatting style] throughout your code.
  
===<tt>static void main()</tt>===
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===<tt>static void main(String[] args)</tt>===
  
 
Your <tt>main()</tt> should do the following:
 
Your <tt>main()</tt> should do the following:
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===<tt>static void heronsFormula()</tt>===
 
===<tt>static void heronsFormula()</tt>===
  
<br>[[Image:Triangle_with_notations_2.svg.png|left|300px]]<br>
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You will compute several geometric identities involving a general triangle with sidelengths ''a'', ''b'', and ''c'' as shown below.
  
You will compute several geometric identities involving a general triangle with sidelengths ''a'', ''b'', and ''c'' as shown belowYour function should:
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<!--<br>[[Image:Triangle_with_notations_2.svg.png|center|300px]]<br>-->
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  [[Image:Triangle_with_notations_2.svg.png|300px]]
  
* Declare these variables as <tt>double</tt>, prompt the user to enter them, and read each in using the [http://docs.oracle.com/javase/7/docs/api/java/util/Scanner.html <tt>Scanner</tt>] class.
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Your function should:
* [http://en.wikipedia.org/wiki/Heron%27s_formula Heron's Formula] gives a method to compute the area ''A'' of the triangle (ignore the fact that A is also the name of one of the triangle vertices). Follow the [http://en.wikipedia.org/wiki/Heron%27s_formula link] and use the first formula to:
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* Declare these sidelength variables as <tt>double</tt>, prompt the user to enter them, and read each in using the [http://docs.oracle.com/javase/7/docs/api/java/util/Scanner.html <tt>Scanner</tt>] class.
** Derive the ''semi-perimeter'' ''s'' and ''A'' from ''a'', ''b'', and ''c'' using [http://docs.oracle.com/javase/7/docs/api/java/lang/Math.html Java math] expressions and/or functions
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* [http://en.wikipedia.org/wiki/Heron%27s_formula Heron's Formula] gives a method to compute the area ''A'' of the triangle (ignore the fact that A is also the name of one of the triangle vertices). Follow the [http://en.wikipedia.org/wiki/Heron%27s_formula link] and use the first formula to:
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** Derive the ''semi-perimeter'' ''s'' and area ''A'' from ''a'', ''b'', and ''c'' using [http://docs.oracle.com/javase/7/docs/api/java/lang/Math.html Java math] expressions and/or functions
 
** Report both ''s'' and ''A'' with <tt>System.out.println()</tt>.
 
** Report both ''s'' and ''A'' with <tt>System.out.println()</tt>.
 
* The [http://en.wikipedia.org/wiki/Law_of_cosines Law of Cosines] can be used to calculate the angle ''γ'' (gamma) between ''a'' and ''b'' (second formula in Applications section of [http://en.wikipedia.org/wiki/Law_of_cosines#Applications link]).  <tt>Math.acos()</tt> will give the angle in radians; please convert it to degrees and report it with <tt>System.out.println()</tt>
 
* The [http://en.wikipedia.org/wiki/Law_of_cosines Law of Cosines] can be used to calculate the angle ''γ'' (gamma) between ''a'' and ''b'' (second formula in Applications section of [http://en.wikipedia.org/wiki/Law_of_cosines#Applications link]).  <tt>Math.acos()</tt> will give the angle in radians; please convert it to degrees and report it with <tt>System.out.println()</tt>
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This method should ask the user to enter an integer which represents a length of time ''t'' in seconds, and then compute and print out the number of ''d'' days, ''h'' hours, ''m'' minutes, and ''s'' seconds corresponding to ''t'' on separate lines.   
 
This method should ask the user to enter an integer which represents a length of time ''t'' in seconds, and then compute and print out the number of ''d'' days, ''h'' hours, ''m'' minutes, and ''s'' seconds corresponding to ''t'' on separate lines.   
  
When you are satisfied that you can calculate ''d'', ''h'', ''m'', and ''s'' correctly, use branching to modify your printing so that (1) you start with the first non-zero time unit (i.e. do not print leading zero values), and (2) you print "1 day" instead of "1 days", "1 hour" instead of "1 hours", etc. where appropriate (i.e., do not use plural for a value of 1).  Some example outputs are below:   
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When you are satisfied that you can calculate ''d'', ''h'', ''m'', and ''s'' correctly, use branching to modify your printing so that you:
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* Start with the first non-zero time unit (i.e. do not print leading zero values)
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* Print "1 day" instead of "1 days", "1 hour" instead of "1 hours", etc. where appropriate (i.e., do not use plural for a value of 1).  Some example outputs are below:   
  
 
If the user inputs "67", the output should be  
 
If the user inputs "67", the output should be  

Latest revision as of 21:42, 26 February 2017

Lab #1 tests

  • Download Android Studio and install it on your machine
  • Either on your machine or on an eCalc machine in lab:
    • Make a new project following these instructions
    • Confirm that you can build and run it (by pressing the green triangle button or choosing "Run" from the Run menu)
    • Add your name and section number in a comment before the class declaration
    • As explained in the subsections below, modify static void main() and create two other methods: static void heronsFormula() { ... } and static void convertSeconds() { ... }
  • Submit your MyClass.java on Sakai by Friday, February 17

Use proper naming and formatting style throughout your code.

static void main(String[] args)

Your main() should do the following:

  • Tell the user (using println()) that they can choose either of the two functions above
  • Prompt the user to enter a number to choose one of the options (1 for Heron's, 2 for convert seconds) and use the Scanner class to read it
  • If a valid choice is made, call the corresponding function immediately. Otherwise print an error message
  • Let the program end (no loop -- just print prompt, read response, and execute one time)

static void heronsFormula()

You will compute several geometric identities involving a general triangle with sidelengths a, b, and c as shown below.

Triangle with notations 2.svg.png

Your function should:

  • Declare these sidelength variables as double, prompt the user to enter them, and read each in using the Scanner class.
  • Heron's Formula gives a method to compute the area A of the triangle (ignore the fact that A is also the name of one of the triangle vertices). Follow the link and use the first formula to:
    • Derive the semi-perimeter s and area A from a, b, and c using Java math expressions and/or functions
    • Report both s and A with System.out.println().
  • The Law of Cosines can be used to calculate the angle γ (gamma) between a and b (second formula in Applications section of link). Math.acos() will give the angle in radians; please convert it to degrees and report it with System.out.println()
  • You might notice a lot of decimal places printed in your answers. Change your println() to format as necessary to only print 2 digits after the decimal for s, A, and γ.

static void convertSeconds()

This method should ask the user to enter an integer which represents a length of time t in seconds, and then compute and print out the number of d days, h hours, m minutes, and s seconds corresponding to t on separate lines.

When you are satisfied that you can calculate d, h, m, and s correctly, use branching to modify your printing so that you:

  • Start with the first non-zero time unit (i.e. do not print leading zero values)
  • Print "1 day" instead of "1 days", "1 hour" instead of "1 hours", etc. where appropriate (i.e., do not use plural for a value of 1). Some example outputs are below:

If the user inputs "67", the output should be

1 minute
7 seconds

and if they input "8880" the output should be

2 hours
28 minutes
0 seconds

For this function you may assume that t is positive, and you do not have to use a long