Quiz 1

Quiz 1: Algorithmic Thinking, Variables, and Operators

Question 1

In your own words, what is an algorithm, and how does it differ from a program? (2-3 short sentences)

Answer

An algorithm is is a process, set of rules, or set of instructions which, when followed, produces some specific output. An algorithm can be and is often used by a computer, but this is NOT necessarily the case.

A program, as we use it in this class, is a series of commands which the computer executes. A program can contain an algorithm.

Question 2

Imagine you have the following file, called Greeting.java.

Greeting.java:

class Greeting {
    public static void main(String[] args) {
        System.out.println("Hello students.\nHow are you?");
    }
}

A. What will this program output to the console? Write it down as you would see it displayed.

Answer

The "\n" is a linebreak, consisting of an escape character and the character n to show that we mean to put in a linebreak. So the final output is:

Hello students.
How are you?


B. What commands would you have to input into your terminal to compile and run this program? Write them down in the order you would enter them. (Assume you are already in the correct directory.)

Answer 
javac Greeting.java 
java Greeting

Question 3

Circle all of the valid statements below.

  1. String message;
  2. String message = "Hello";
  3. String value = 123;
  4. int 7;
  5. int x = "7";
  6. double y = 3;
  7. double z = 3.0 + 0.4;
Answer

1, 2, 6, and 7 are all valid. Note that 6 is bad style, but is perfectly fine.

3 is not valid because it assigns an integer to a string. 4 is not valid because variable names cannot start with numbers. 5 is not valid because it assigns a string to an integer.