CS 1301 Program 1 Fall 2014

Educational Goals: The educational goals of this program are that the student should use the concepts of

• design with pseudocode
• output of prompts and labels to match specified output
• input of values from the keyboard
• translating algebraic equations into Java expressions
• using math library functions
• calculations in assignment statements
• priority of arithmetic operations
• documentation
• testing with valid inputs and invalid inputs

Imagine you work for an ATC (air traffic control) tower, located at point O (observer, see figure above). The radar system detects the distance from O to each of the two aircrafts - d1 and d2, as well as the angle theta. You are asked to determine distance D, given d1, d2 and theta.

The problem is an application of the Cosine Law.

The general case:

In our particular case, D can be computed as follows:

Sample interaction with the program:

----jGRASP exec: java program1
***ATC  computation***

Enter the distance between observer and aircraft one: 72
Enter the distance between observer and aircraft two: 50
Enter the angle theta between them: 49
The distance between the aircraft is: 54.40932816409653
 ----jGRASP: operation complete.

Another example run:

 ----jGRASP exec: java program1
***ATC  computation***

Enter the distance between observer and aircraft one: 50
Enter the distance between observer and aircraft two: 50
Enter the angle theta between them: 45
The distance between the aircraft is: 38.268343236508976
 ----jGRASP: operation complete.

Another example run:

 ----jGRASP exec: java program1
***ATC  computation***

Enter the distance between observer and aircraft one: 100
Enter the distance between observer and aircraft two: 100
Enter the angle theta between them: 360
The distance between the aircraft is: 0.0
 ----jGRASP: operation complete.

A few details

Please note that theta is measured in degrees. Java Math.cos() function takes arguments in radians not degrees. You need to convert the input from the user (given in degrees) to radians. This can be done in several ways, either way is acceptable.

Test Cases

First, read the assignment carefully. Look for how the program is supposed to behave. You do not know what the code looks like - that is fine. The assignment gives some examples of normal runs. There are other test cases needed.
Save this doc file and fill in the table with test cases. Put your name and the section at the top. Submit this file with your additions at the link here. Choose the menu choices of "TestCases" and "Program 1". This is due by Wednesday, September 10th, 11:59PM.

Design

// supply program prolog
//  main function
    // 1. Display introductory message 
    // (some of your design here)
    // N. calculate distance between the aircrafts
    // (rest of design goes here)
    // M. output to the shell the distance

Implement the design

There are several specifications about how your program should be written.

• This program uses input; you will have to prompt the user for d1, d2 and theta.
• Your program should handle either kind of number, integer or floating point. You really do not have to do anything extra to make this happen.
• Use assignment statements to perform the calculations. not output statements.
• You must use at least one function from the math library.
• Make sure you format the lines of the output as described. The line breaks and the punctuation should be as shown. The output messages should be exactly as given.

Please read the documentation standard on the class web page. As you can see from looking at the grading criteria, we will be looking to see how you meet these standards. Note particularly that we require a prolog!

Remember that the program must run with NO errors or warnings. If it does not, it will not be graded!