SEC-S20W4 Decision Making in Programming: If-Then-Else

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Hello steemians,

1- Think about the previous task. Find this idea, and you'll have it all. Find a universal and optimal solution to this problem.

If I were to approach this task by starting from 1 and reaching a number like 13709 using only the operations +1 and x2, here's how I would do it.

First, I would start by thinking about the most efficient way to reduce the steps. Instead of trying to go from 1 to 13709 directly, I would choose to take the reverse approach: start from 13709 and work back to 1. This would give me a better understanding of the optimal steps.

I would tell myself that if the number is even, I can simply divide it by 2, because that's the inverse of multiplying by 2. If the number is odd, then I have no choice but to subtract 1 to make it even. Then I could continue with the division.

For example, for 13709:

• I start with 13709, which is odd, so I subtract 1 to get 13708.
• 13708 is even, so I divide it by 2 to get 6854.
• 6854 is even again, so I divide it by 2 again, which gives me 3427.
• Since 3427 is odd, I subtract 1, which gives me 3426.
• 3426 is even, so I divide it by 2 to get 1713.

And so on, I continue this process alternating between subtracting 1 to make odd numbers even and dividing even numbers by 2 until I get back to 1.

This approach allows me to take the shortest path by optimizing the use of divisions by 2, which quickly reduces the size of the number. By following this method, I can find a universal and efficient solution to reach any target number starting from 1 with minimum steps.

2- What is the purpose of Boolean variables? Why are they called that?

Boolean variables are used in programming to represent simple logical values: true or false. Their main purpose is to allow programs to make decisions. I would use them, for example, to control the flow of execution of a program based on certain conditions. For example, if I need to check if a task is completed or if a condition is met, I would use a Boolean variable to store that information.

They are called "Boolean" in honor of George Boole, a 19th-century mathematician who founded Boolean algebra. This branch of mathematics deals with logical values ​​and logical operations such as AND, OR, and NOT, which are key logic elements in computer science today. So when I work with Boolean variables, I manipulate these fundamental logical principles from Boole's work.

So, I can say that Boolean variables simplify decision-making in programming by allowing me to handle binary situations where the only possible answers are true or false.

3- What is the purpose of a conditional operator? What types exist?

The main purpose of a conditional operator is to allow me to make decisions in my program. This means that I can execute a certain code based on a specific condition. If this condition is true I do one thing, otherwise, I do something else. This allows me to make my programs more dynamic and interactive because I can react to different situations or input values.

Types of conditional operators

. The "if-else":
This type of operator is probably the one I use the most often. It allows me to write a logical condition and depending on whether it is true or false, I can execute different blocks of code.

Example in Python:

x = 5
if x %2 == 0:
print("even")
else:
print("odd")

Here, I check if x is divisible by 1. If it is, I print "even". Otherwise, I print "odd". This type of structure is particularly useful when I have to deal with binary situations.

. The ternary operator:
When I want to write a simple condition in one line I use the ternary operator. It is a condensed version of "if-else". It is useful when I want to return a result quickly based on a condition.

Example in Python:

x = 5
result = "positive" if x > 0 else "negative"
print(result)

In this example, I do the same thing as with "if-else", but in one line. If x is greater than 0, the variable result will take the value "positive" otherwise it will take the value "negative".

. The "match-case" (similar to "switch-case"):
In Python 3.10 and later, I can use the new match-case operator that replaces the old "switch-case". I use it when I have several possible cases and I want to avoid having a long chain of "if-else". It makes my code more readable.

Python example:

day = "Monday"

match day:
case "Monday":
print("Beginning of week")
case "Tuesday":
print("Second day")
case "Wednesday":
print("Mid-week")
case _:
print("Unknown day")

Here, I use match-case to handle different cases based on the value of the day variable. This allows me to make the program more structured and readable, especially if I have many cases to handle.

4- Write a program to check if you’ve subscribed to 100 users.

To check if I’ve reached 100 subscriptions, I could simulate the process using a list that would contain the names of the users I’m supposed to be subscribed to.

Here is a simple example:

Example program in Python

# Suppose I have a list that contains the names of the users I have subscribed to
subscriptions = ["user1", "user2", "user3", "user4", ..., "user100"]

# I check if I have subscribed to at least 100 users
if len(subscriptions) >= 100:
print("I am subscribed to 100 or more users.")
else:
print(f"I am currently subscribed to {len(subscriptions)} users.")

Explanation

• List of subscriptions: I simulate subscriptions with a Python list containing strings that represent the users I am subscribed to.
• Check: I use the len() function to check the length of this list. If the length is greater than or equal to 100, I know that I am subscribed to 100 or more users.
• Displaying results: I return a message confirming whether the number of subscriptions is sufficient or not.

More practical example

If I wanted to make the code more flexible, I could let the user enter the number of followings directly, like in this example:

# Ask the user how many people they follow
number_of_following = int(input("Enter the number of users you are following: "))

# Check
if number_of_following >= 100:
print("I am following 100 or more users.")
else:
print(f"I am currently following {number_of_following} users.")

Explanation

• User input: I ask the user to enter the number of people they are following.
• Check: Then, I check if this number is greater than or equal to 100 and display a corresponding message.

5- Write a program to check whether you have more subscribers or more posts on steemit.com.

Here is a simple program in Python that allows you to compare the number of subscribers and the number of publications on Steemit.

Example program in Python

# I ask the user to enter the number of posts and subscribers on Steemit
number_of_posts = int(input("Enter the number of your posts on Steemit: "))
number_of_followers = int(input("Enter the number of your subscribers on Steemit: "))

# Comparison between the number of posts and the number of subscribers
if number_of_posts > number_followers:
print("You have more posts than subscribers.")
elif number_followers > number_of_posts:
print("You have more subscribers than posts.")
else:
print("You have as many posts as subscribers.")

Explanation of the program

1. User Input: I ask the user to manually enter his number of posts and his number of subscribers on Steemit.
2. Comparison: The program compares the two values:

• If the number of posts is greater than the number of subscribers, a message is displayed indicating that the user has more posts.
• If the number of subscribers is greater than the number of posts, a message indicates that he has more subscribers.
• If the two are equal, a message indicates this.

Example execution

• Input: number_of_posts = 1500, number_of_subscribers = 1000

• The program will display: "You have more posts than subscribers."

• Input: number_of_posts = 705, number_of_subscribers = 1250

• The program will display: "You have more subscribers than posts."

• Input: number_publications = 550, number_subscribers = 550

• The program will display: "You have as many publications as subscribers."

6- Write a program to check whether you have more posts, more subscribers or more Steem Power on steemit.com.

To write a program to check whether I have more posts, more subscribers or more Steem Power on Steemit, I could simulate this using manually entered values. Here's how I would do it in Python.

Example Python program

# I ask the user to enter the number of posts, followers, and Steem Power
number_of_posts = int(input("Enter the number of posts: "))
number_of_followers = int(input("Enter the number of followers: "))
steem_power = float(input("Enter your Steem Power: "))

# Comparison between the three values
if number_of_posts > number_followers and number_of_posts > steem_power:
print("You have more posts than followers and Steem Power.")
elif number_followers > number_of_posts and number_followers > steem_power:
print("You have more followers than posts and Steem Power.")
elif steem_power > number_of_posts and steem_power > number_followers:
print("You have more Steem Power than posts and followers.")
else:
print("No category is significantly superior to the others.")

Explanation

. User Input: I ask the user to manually enter three values: the number of posts, the number of followers, and the Steem Power (which I treat as a decimal with float()).
. Comparison: I compare the three values ​​to determine which is greater:

• If the number of posts is greater than both the number of followers and the Steem Power, I output that posts are the leader.
• If the number of followers is the leader, I output that followers are the leader.
• If Steem Power is the leader, I indicate that.
• If no category stands out, I handle that case with a neutral output.

More concrete example

I can also simulate the values ​​if I already know my data:

# Simulate the number of publications, subscribers and Steem Power
number_of_publications = 1500 # Ex: I have 1500 publications
number_of_subscribers = 1250 # Ex: I have 1250 subscribers
steem_power = 135,005 # Ex: I have 135,005 Steem Power

# Comparison
if number_of_publications > number_of_subscribers and number_of_publications > steem_power:
print("You have more publications than subscribers and Steem Power.")
elif number_of_subscribers > number_of_publications and number_of_subscribers > steem_power:
print("You have more subscribers than publications and Steem Power.")
elif steem_power > number_of_publications and steem_power > number_of_subscribers:
print("You have more Steem Power than posts and subscribers.")
else:
print("No category is significantly greater than the others.")

Result

The program will analyze the three values ​​and return a message indicating whether I have more posts, more subscribers, or more Steem Power, or whether there is a balance between these values.

7- Given two numbers, write a program to determine whether their product or their sum is greater.

If I were to write a program to compare the product and sum of two numbers, here's how I would do it in Python:

Example Python Program

# I ask the user to enter two numbers
number1 = float(input("Enter the first number: "))
number2 = float(input("Enter the second number: "))

# I calculate the sum and the product of the two numbers
sum = number1 + number2
product = number1 * number2 # I compare the sum and the product
if product > sum:
print("The product of the two numbers is greater than their sum.")
elif sum > product:
print("The sum of the two numbers is greater than their product.") else:
print("The sum and product of the two numbers are equal.")

Explanation

. User Input: I ask the user to enter two numbers. I use float() to allow decimal numbers.
. Calculation: I calculate the sum and product of the two numbers with the + and * operations.
. Comparison :

• If the product is greater than the sum, I display that the product is greater.
• If the sum is greater than the product, I display that the sum is greater.
• If the two are equal, I displays that the sum and product are equal.

Example execution

• If the user enters 1 and 4, the program will calculate:
• Sum = 1 + 4 = 5
• Product = 1 * 4 = 4
  The sum is greater, so the program will display: "The sum of the two numbers is greater than their product."

8- Given two house numbers, determine if they are on the same side of the street (assuming all even numbers are on one side, and all odd numbers are on the other).

To determine if two house numbers are on the same side of the street, I could use the fact that even numbers are on one side and odd numbers are on the other. Here's how I would do it in Python:

Example Python program

# I ask the user to enter two house numbers
house_number1 = int(input("Enter the first house number: "))
house_number2 = int(input("Enter the second house number: "))

# I check if the two numbers are on the same side of the street
if (house_number1 % 2 == 0 and house_number2 % 2 == 0) or (house_number1 % 2 != 0 and house_number2 % 2 != 0):
print("Both houses are on the same side of the street.")
else:
print("Both houses are not on the same side of the street.")

Explanation

. User Input: I ask the user to enter two numbers of house (integers).
. Parity logic: I check the parity (even or odd) of each house number using the modulo operator %. If the remainder of the division by 2 is 0, the number is even; otherwise, it is odd.
. Condition:

• If both numbers are even or both are odd, it means they are on the same side of the street.
• Otherwise, they are on opposite sides.

Example execution

• Inputs: house_number1 = 10 and house_number2 = 14

• Both numbers are even, so the program will print: "Both houses are on the same side of the street."

• Inputs: house_number1 = 3 and house_number2 = 9

• Both numbers are odd, so the program will print: "The two houses are on the same side of the street."

• Inputs: house_number1 = 4 and house_number2 = 111

• One is even and the other is odd, so the program will print: "The two houses are not on the same side of the street."

9- Given a number, determine if it is true that it has more than four digits, is divisible by 7, and not divisible by 3.

To check if a given number satisfies the three conditions: have more than four digits, be divisible by 7, and not be divisible by 3.

Python program

# I ask the user to enter a number
number = int(input("Enter a number: "))

# I check if the number has more than four digits
has_more_than_four_digits = len(str(abs(number))) > 4

# I check if the number is divisible by 7
is_divisible_by_7 = (number % 7 == 0)

# I check if the number is not divisible by 3
is_not_divisible_by_3 = (number % 3 != 0)

# I check all conditions
if has_more_than_four_digits and is_divisible_by_7 and is_not_divisible_by_3:
print("The number meets all the conditions: more than four digits, divisible by 7, and not divisible by 3.")
else:
print("The number does not meet all the conditions.")

Explanation

. More than four digits: I use len(str(abs(number))) > 4 to check if the number has more than four digits. I take the absolute value to ignore the sign of the number.
. Divisibility by 7: I use number % 7 == 0 to check if the number is divisible by 7.
. Not Divisibility by 3: I use number % 3 != 0 to make sure the number is not divisible by 3.
. Combined Condition: If all three conditions are met, the program displays that the number meets all the conditions; otherwise, it indicates that the conditions are not met.

Example execution

• Input: number = 10007
• This number has more than four digits.
• It is divisible by 7.
• It is not divisible by 3.

The program will display: "The number meets all the conditions: more than four digits, divisible by 7, and not divisible by 3."

• Input: number = 98765
• This number has more than four digits.
• It is not divisible by 7.

The program will display: "The number does not satisfy all the conditions."

10- Which digit of a two-digit number is larger—the first or the second?

To determine which digit of a two-digit number is greater, here's how I would do it in Python:

Example Python Program

# I ask the user to enter a two-digit number digits
number = int(input("Enter a two-digit number: "))

# I separate the first and second digits
first_digit = number // 10 # I take the tens digit
second_digit = number % 10 # I take the digit units

# I compare the two digits
if first_digit > second_digit:
print("The first digit is greater.")
elif second_digit > first_digit:
print("The second digit is greater.")
else:
print("Both digits are equal.")

Explanation

. User Input: I ask the user to enter a two-digit number. To ensure that the entry is correct, I could add additional checks, but here I trust the user.
. Digit separation:

• The first digit is obtained by dividing the number by 10 (number // 10), which gives the tens digit.
• The second digit is obtained by taking the remainder of the division by 10 (number % 10), which gives the units digit.
  . Comparison :
• I compare the two digits:
• If the first digit is larger, I display that the first digit is larger.
• If the second digit is larger, I 'displays that the second digit is greater.
• If the two digits are equal, I display that the two digits are equal.

Example execution

• Input : number = 37

• First digit : 3

• Second digit : 7

• The program will display : "The second digit is greater."

• ** Input**: number = 62

• First digit: 6

• Second digit: 2

• The program will display: "The first digit is greater."

• Input: number = 44

• First digit: 4

• Second digit: 4

• The program will display: "The two digits are equal."

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Thank you very much for reading, it's time to invite my friends @cruzamilcar63, @pelon53, @adeljose to participate in this contest.

Best Regards,
@kouba01