Count the black squares (one colour per input)

Challenge Level: Beginner

This programming challenge is linked to the following lessons:

Challenge 1.1 for Parity magic (8 to 10)

Learning outcomes

Students will be able to:

Explain the difference between the set statement and the change statement when used to update the value of a variable.
Computer Science: Programming
Explain what you need to consider if you are asking for an input from the end user.
Computer Science: Programming
Identify when to use an if statement to check a set of conditions.
Computer Science: Programming

Requirement:

Create a program which asks the user to enter 5 black or white squares (B for black or W for white) one at a time and outputs the total number of black squares.

Testing examples:

Your program should display the outputs shown in this table for the given inputs provided:

Input	Output
B W W B W	2
B B B B B	5
W W W W W	0

Languages

Scratch

What it should look like

Click on the green flag, enter the inputs provided in the “testing examples” to see the expected output of your program.

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Recommended blocks

when green flag clicked

ask [Please enter a black or white square (B for black or W for white):] and wait

say (black cards total)

set [black cards total v] to [0]

change [black cards total v] by (1)

repeat (5)
end

if <(answer) = [B]> then
end

Hints

To store the total number of black cards, create a variable called “black cards total”. You need to increase the value of this variable every time the user enters a black card. Display the value of “black cards total” at the end.
Use the repeat () block to run the blocks inside a specified number of times. In this challenge you need to repeat the blocks 5 times.
The if <> then block checks if the condition is true and then runs the blocks inside of the IF block.

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