Basic programming course: Lesson #2 - Variables and Types of Data.

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Hello Steemit friends!

1. What are variables and what are they used for?

Variables are storage spaces that allow information to be stored in a program. They play a vital role in computer science because they allow data to be manipulated dynamically. When I explain this concept to my students, I often compare variables to storage boxes in which you can place different objects (the data) each box having a label (the variable name) and a specific type of object that it can contain (the data type).

When I want to explain the importance of variables to my students, I often use a simple example like the pen example. I ask them to give me a pen without reaching out or pointing to a specific place to put it.

They often look at me puzzled, and that's when I explain: "You can't give me the pen because I didn't tell you where to put it." In computer science, it's the same thing. If we want to store data (like the pen in this example), we must first designate a location where to put it, this is called a variable. The variable is like a hand or a box that allows us to keep the data safe so that we can use it later.

So, in the same way that they would need to know where to put the pen to give it to me a program needs to know where to store information to manipulate it effectively.

Source

2. Assign a type of data to the following variables and explain why:

• email: Character

  • Why: An email address consists of a combination of letters, numbers, and symbols (e.g., [email protected]), which makes it a sequence of characters. In most programming languages, strings are used to store textual data.

• phone: Character (or Integer depending on usage)

  • Why: While phone numbers may appear to be numerical, they often include special characters like "+" or dashes ("-"). In many cases, phone numbers are treated as strings to preserve formatting. If strictly numerical without special characters, Integer can be used.

• working_hours: Integer or Real

  • Why: Working hours typically represent a numerical value, either in whole hours (Integer, e.g., 7 hours) or in decimal form (Real, e.g., 6.5 hours for 6 hours and 30 minutes).

• price_steem: Real

  • Why: The price of STEEM (or any cryptocurrency) fluctuates and often includes decimal points (e.g., 0.25 or 1.25 USD). Therefore, Real is the most appropriate type for precisely handling these values.

• age: Integer

  • Why: Age is typically a whole number that represents the number of years. Therefore, Integer is the best fit for this variable.

3. Explain how the following code works:

Algorithm names
    Define name, last_name as Character;
    
    Print "Enter your name:";
    Read name;
    Print "Enter your last name:";
    Read last_name;
    
    Print "Hello " name " " last_name ", welcome";
EndAlgorithm

Explanation:

Step	Description
Define name, last_name as Character	Declare the variables name and last_name to store strings (text).
Print "Enter your name:"	Display a message asking the user to enter their first name.
Read name	The program waits for the user to enter their first name and stores this entry in the variable name.
Print "Enter your last name:"	Displays a message asking the user to enter their last name.
Read last_name	The program waits for the user to enter their last name and stores this entry in the variable last_name.
Print "Hello " name " " last_name ", welcome"	The program concatenates "Hello", the first name (name), a space, the last name (last_name), and the string ", welcome", and then displays the complete message. e.g., "Hello Bouchamia Bilel, welcome."

4. Develop a pseudo-code to calculate the value in USD of X STEEM.

Algorithm steem_to_usd

     Define  price_steem, amount_steem, total as Real;

// Request the user to input the necessary data
     Print "Enter the current price of STEEM in USD:";
     Read price_steem;

     Print "Enter the amount of STEEM you have:";
     Read amount_steem;

// Calculate the total value in USD
     total = price_steem * amount_steem;

// Show the result
     Print "The total value of your STEEM in USD is: " total;

EndAlgorithm

_{Screenshot taken from the PSeInt application}

_{Screenshot of the algorithm execution}

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Thank you very much for reading, it's time to invite my friends @josepha, @lhorgic, @mohammadfaisal to participate in this contest.

Best Regards,
@kouba01