Testing First Set of Programs

Setting up Programming Environment

Although you can use an IDE, such as, NetBeans, IntelliJ IDEA, and Eclipse that has already been installed by someone or use even an online IDE, such as, https://replit.com/, it is benefical to understand the basic concepts of operating systems, JRE, JDK, and Editors for Programmers.

To set up a Java programming environment on a system, you don’t have to have the Administrative privilege of system.

  1. If you are using a Windows computer, download and set up Git. Go to https://git-scm.com/download/win, download the “64-bit Git for Windows Portable.” It is a “.exe” file, you can run the file (by double-clicking at it, for instance).
  2. Download and set up Atom Editor. Go to https://atom.io/. Download and run the downloaded file.
  3. Download and set up JDK. Go to https://jdk.java.net/archive/ and download OpenJDK 17. This is a zip file. Simple unzip it.

Refer to Programming Tools and Environments for details.

Writing and Testing the “Hello, World!” Program

Following the instruction in the Overview lecture slides

Computing the Area of a Circle

Write a program called AreaOfCircle.java that computes the areas of the circle whose radius is 5.8 and print out the area on the standard output. To do this, you need the mathematical constant $\pi$. Java provides a constant in its Math package called Math.PI that you should use in your program.

Calculating GPA from Two Courses

Write a program called GPACalculator.java that reads GPA value and credit hours for two courses from standard input and compute GPA of the two courses, and print the GPA on the standard output. The GPA is computed using the following formula

GPA = ((GPA Value 1)(Credits 1)+(GPA Value 2)(Credits 2) ) /((Credits 1)+(Creits 2))

For example, a user enters

4.0 3

3.0 3

The program computes the GPA, and displays the GPA as,

GPA is 3.5.