Ternary conditional operator in Swift - Step-by-Step Execution

Concept Flow - Ternary conditional operator

Evaluate condition

Yes↓

Use value if true

↓

End

No↓

Use value if false

↓

End

The ternary operator checks a condition and chooses one of two values based on true or false.

Execution Sample

Swift

let age = 20
let canVote = age >= 18 ? "Yes" : "No"
print(canVote)

This code checks if age is 18 or more and sets canVote to "Yes" or "No" accordingly.

Execution Table

Step	Condition (age >= 18)	Result	Value chosen	Output
1	20 >= 18	true	"Yes"	canVote = "Yes"
2	End	-	-	Prints: Yes

💡 Condition true, so "Yes" chosen and printed.

Variable Tracker

Variable	Start	After Step 1	Final
age	20	20	20
canVote	undefined	"Yes"	"Yes"

Key Moments - 2 Insights

Why does canVote get "Yes" and not "No"?

Because the condition age >= 18 is true at step 1 in the execution table, so the true value "Yes" is chosen.

What if age was 16? What value would canVote get?

If age was 16, the condition would be false, so the false value "No" would be chosen instead, as shown by the ternary operator logic in the concept flow.

Visual Quiz - 3 Questions

Look at the execution table, what is the value of canVote after step 1?

A "No"

B "Yes"

C undefined

D 20

💡 Hint

Check the 'Value chosen' and 'Output' columns in row 1 of the execution table.

At which step does the program print the output?

A Step 2

B Before step 1

C Step 1

D No output printed

💡 Hint

Look at the 'Output' column in the execution table rows.

If age was 17, what would the ternary operator choose?

A "Yes"

B undefined

C "No"

D Error

💡 Hint

Refer to the concept flow and key moments about condition false choice.

Concept Snapshot

Ternary conditional operator syntax:
condition ? valueIfTrue : valueIfFalse
It evaluates the condition once.
If true, returns valueIfTrue.
If false, returns valueIfFalse.
Used for simple if-else in one line.

Full Transcript

The ternary conditional operator in Swift lets you pick one of two values based on a condition. First, the condition is checked. If it is true, the value after the question mark is chosen. If false, the value after the colon is chosen. For example, if age is 20, the condition age >= 18 is true, so canVote becomes "Yes". Then the program prints "Yes". If age was less than 18, canVote would be "No". This operator is a shortcut for simple if-else statements and helps write cleaner code.