Difference between revisions of "CISC181 S2017 Lab1"
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** Using a ''single-line comment'', disable the "Hello, world" print statement in <tt>main()</tt> | ** Using a ''single-line comment'', disable the "Hello, world" print statement in <tt>main()</tt> | ||
** You will use <tt>main()</tt> to compute several geometric identities involving a general triangle with sidelengths ''a'', ''b'', and ''c'' as shown below. 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.<br>[[Image:Triangle_with_notations_2.svg.png|center|300px]]<br> | ** You will use <tt>main()</tt> to compute several geometric identities involving a general triangle with sidelengths ''a'', ''b'', and ''c'' as shown below. 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.<br>[[Image:Triangle_with_notations_2.svg.png|center|300px]]<br> | ||
− | *** [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 | + | *** [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: |
+ | **** 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 | ||
+ | **** 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> | ||
*** You might notice ''a lot'' of decimal places printed in your answers. Change your <tt>println()</tt> to [http://docs.oracle.com/javase/tutorial/java/data/numberformat.html <tt>format</tt>] as necessary to only print '''2''' digits after the decimal for ''s'', ''A'', and ''γ''. | *** You might notice ''a lot'' of decimal places printed in your answers. Change your <tt>println()</tt> to [http://docs.oracle.com/javase/tutorial/java/data/numberformat.html <tt>format</tt>] as necessary to only print '''2''' digits after the decimal for ''s'', ''A'', and ''γ''. |
Revision as of 11:15, 13 February 2017
- 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
- If you haven't already, paste the following into MyClass: public static void main(String[] args) { System.out.println("Hello, world!"); }
- Confirm that you can build and run it (by pressing the green triangle button or choosing "Run" from the Run menu)
- Modify MyClass.java as follows:
- Add your name and section number as a multi-line comment
- Using a single-line comment, disable the "Hello, world" print statement in main()
- You will use main() to compute several geometric identities involving a general triangle with sidelengths a, b, and c as shown below. Declare these 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 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.
- Use proper naming and formatting style throughout your code.
- 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:
Submit your MyClass.java on Sakai by Friday, February 17