U5Ch1L7_IfStatementsUnplugged

Purpose: Students will begin writing code using If Statements.

Vocabulary:

• Conditionals - Statements that only run under certain conditions.
• If-Statement - The common programming structure that implements "conditional statements".
• Selection - A generic term for a type of programming statement (usually an if-statement) that uses a Boolean condition to determine, or select, whether or not to run a certain block of statements.

Class Question:
Handout:
 With a partner discuss what the difference is between them:
Set #A

• When the button is clicked add one to the score.
• If the button is clicked add one to the score.

Take a moment to discuss with your partner the difference between the two sentences.

Set #B

• When the score reaches 20, set the screen to "game over."
• If the score reaches 20, set the screen to "game over."

Take a moment to discuss with your partner the difference between the two sentences.
What is the difference between “When” & “If”??
There is no right answer. In English both pairs of sentences mean basically the same thing.
However in programming, using the words "if" and "when" map to some expectations about how the underlying code is written.
Here is the difference:
"When" is used in reference to an event -- When something happens respond in such and such a way.
"If" is used in reference to a decision about whether or not to execute a certain piece of code -- If something is true, then do this, otherwise do that.

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