Exercises

2.1

1. A portable program is a program that can be run on a variety of different types of computers without having to change anything.

2. Java’s secure programs and portable nature are two reasons it is better than C++.

3. A thread is a process that can be running while other threads are active, allowing multitasking in programs.

2.2

1. JVM stands for Java Virtual Machine.

2. byte code is the language Java compiles programs into. It is read by the JVM, which acts as an imaginary computer for the purpose of the program.

3. Applets are often shown on websites. these are run by small JVMs incorporated into the web browser, and can be made to do a variety of things, such as display advertisements or interactive site maps.

2.4

1. A program is software that can accomplish a variety of tasks based on its coding and purpose.

2. “println” tells the computer to print whatever is listed after it on the computer screen.

3. “System.out” is used before “println” to define it, and tell the program to display its message in Terminal.

2.5

1. step 1. open notepad and write the program.

step 2. compile the program with the Java compiler “javac myprogram.java”

step 3. run the program with “java myprogram”

2. compile-time errors are errors in the spelling of important details in the code, and keep the Java compiler from compiling the program.

3. a. System.out.println(“Here is an error); this line is missing a ” after the word error.

b.  System.out.println(“Here is another error”; this line is missing closing parentheses after the word error.

4 . Readability helps to allow the user to find errors in the code when revisiting the work, and helps when the user wants to improve the program, it is much easier to do so with readable code.

Hello World Quiz

1. The platform-independent code that the computer compiles the program into is called class.

2. /*comment is not a valid comment.

3. You should check the line that has the word “main” in it for errors.

4. public static void main(String[] args) {

is the correct signature for the main method.

5. “Public” comes before “static”

6. The main method defines the parameters of the code in the program, and that there will be one string of code in the program, as defined by “main(String[] args)”.

Questions questions questions…

1. What is a bit in computer terminology? How many Bits in a Byte? How many bytes in a megabyte, and a Gigabyte?

A bit is the smallest unit of data in a computer system. There are 8 bits in a byte, about 1 million bytes in a megabyte and around 1 billion bytes in a gigabyte. Bits and bytes are used to store data in a computer.

2. Name 3 Computer input devices, 2 output devices.
Keyboard, mouse, and a scanner are all examples of input devices, and the monitor and speakers are examples of output devices.

3.What is a computer network?

A computer network is a group of computers that are connected to each other using a Local Area Connection, or LAN. These computers can communicate with each other while hooked up.

4.What is the difference between hardware and software?

The hard drive, optical disk drive, RAM, CPU, Graphics card and sound card are all examples of hardware, items that are part of the computer that make it work. An example of software is a computer game, or a copy of Microsoft Word, something that is installed on a computer to allow it to perform tasks.

5. What is the difference between application software and system software?

System software is used to govern how the computer system functions, making sure the computer runs smoothly in general. Application software tells the program how to do the tasks that the program was built to do, and nothing else.

6. What is machine language?

Machine language is the code used by the Central Processing Unit of the computer to communicate on the most basic level with the rest of the computer.
7. Name 5 Different programming languages.

Python, Ruby, C++, Java, and Whitespace are all examples of programming languages.

http://en.wikipedia.org/wiki/Whitespace_(programming_language)

8. What is the ACM code of ethics?

The Association for Computing Machinery has produced an ethics code for the use of computers detailing proper usage of computers.

9. What is binary? How would the number 5 be represented in binary? The number 200? The number 1534?

Binary is used on all computers as the basic language. Comprised of only zeros and ones, the computer reads everything as a stream of binary.

the number 5 in binary is 101

the number 200 in binary is 11001000

and the number 1534 in binary is 10111111110

10. What is a character? a String? an Integer? a boolean value?

A character is a single letter, number, or symbol, such as “P” or “^”. a String is a series of characters, such as a line of code or a sentence in English. An integer is a single number, such as 2348672. A boolean value is a piece of information based in a binary-like system. Boolean reduces things to either “true” or “false”.

What is programming?

Programming is the act of writing and stringing together code to make programs. These programs can accomplish a huge variety of tasks. The more complex the code is, the more intricate and complex the final program will be.

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