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Challenge 7.2

Display the binary cards needed to represent any decimal number

Challenge Level: Ready to expand


Write a program that asks the user to enter any decimal number as the input and displays the binary cards representing that number (B for displaying black cards with no dots, and W for displaying white cards with dots) as the output.

  • Make variables called:

    • original and set its value to the input number given by the end user.
    • number and set its value to original (so we can use original later)
    • bit_value and set its value to 1. Find the smallest bit value which is larger than the number by doubling value of bit_value while it is smaller than or equal to number.
    • cards is a string variable and stores the binary cards needed (‘B’ for black cards and ‘W’ for white cards).
  • Set the variable bit_value to 1 and find the smallest bit_value which is larger than number by multiplying bit_value by 2 while it is smaller than or equal to number. You can do this by using a while loop.

  • Now divide the bit_value by 2 and check if number is greater than or equal to bit_value. If it is, add ‘W’ to string variable cards and subtract bit_value from the number. If not, add ‘B’ to string variable cards. Repeat while bit_value is greater than 1. Display the value of cards as the output.

  • Test your program with some values on the boundaries (for example test it with numbers 255 and 256).

Programming Reminders
# Print a string directly
print("Hello World!")

# Print a variable


# Set a variable as a string
fruit_name = "Apple"

# Set a variable as an integer 
pieces_of_fruit = 7

# Set a variable from a calculation
cost_of_fruit = pieces_of_fruit * cost_per_item

# Add one to a value
pieces_of_fruit += 1


# Find out the discount on fruit
if pieces_of_fruit > 100:
   print("Bulk discount applies")
elif pieces_of_fruit > 5:
   print("Discount applies")
   print("No discount")

For loops

# Print numbers 0-9 - remember Python starts counting from 0 
for num in range(10):

While loops

# Print numbers 0-9 using a while loop and a variable
num = 0
while num < 10:

    # Increment the variable by one.
    # It will prevent an infinite loop!
    num += 1 


# Create a list of fruit 
fruit = ["Apple", "Banana", "Orange", "Pear"]


# Create a function which prints a greeting
def greeting(name):
    print("Hello " + name)

# Call the function

Enter your code in the editor below

Your results will be displayed here

Input Expected output Received output Status
The binary representation for the number 11 is WBWW

Not yet run ?
The binary representation for the number 255 is WWWWWWWW

Not yet run ?
The binary representation for the number 256 is WBBBBBBBB

Not yet run ?