Semicolons are optional behavior in Swift - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to print a message without using a semicolon.

Swift

print("Hello, Swift")[1]

Drag options to blanks, or click blank then click option'

A.

B;

C:

D(nothing)

Attempts:

3 left

💡 Hint

Common Mistakes

Adding a semicolon when it is not required.

Using other punctuation marks like colon or period.

In Swift, semicolons are optional at the end of a line. You can leave it empty.

2fill in blank

medium

Complete the code to declare two variables on the same line using a semicolon.

Swift

var a = 5[1] var b = 10

Drag options to blanks, or click blank then click option'

A;

B:

C,

D.

Attempts:

3 left

💡 Hint

Common Mistakes

Using a comma instead of a semicolon.

Using a colon or period which are not statement separators.

When declaring multiple statements on the same line in Swift, you separate them with a semicolon.

3fill in blank

hard

Fix the error by adding or removing the semicolon correctly.

Swift

let x = 10[1]
let y = 20

Drag options to blanks, or click blank then click option'

A;

B:

C(nothing)

D,

Attempts:

3 left

💡 Hint

Common Mistakes

Adding a semicolon when it is not needed.

Using colon or comma which cause syntax errors.

In Swift, semicolons are optional at the end of a line. Removing the semicolon here is correct.

4fill in blank

hard

Complete the code to write two print statements on the same line correctly.

Swift

print("Hello"); print("World")[1]

Drag options to blanks, or click blank then click option'

A;

B(nothing)

C:

D,

Attempts:

3 left

💡 Hint

Common Mistakes

Using commas or colons instead of semicolons.

Adding a semicolon after the last statement unnecessarily.

Use a semicolon to separate statements on the same line. The last statement does not need a semicolon.

5fill in blank

hard

Complete the code to declare three variables on the same line correctly.

Swift

var x = 1; var y = 2; var z = 3[1]

Drag options to blanks, or click blank then click option'

A;

B(nothing)

C:

D,

Attempts:

3 left

💡 Hint

Common Mistakes

Using commas or colons instead of semicolons.

Adding a semicolon after the last statement unnecessarily.

Use semicolons to separate multiple statements on the same line. The last statement does not need a semicolon.

Practice

1. In Swift, when are semicolons required at the end of statements?

easy

A. Never, semicolons are not used in Swift

B. Always at the end of every statement

C. Only after function declarations

D. Only when multiple statements are on the same line

Solution

1. Step 1: Understand Swift statement endings

   Swift allows statements to end without semicolons if each is on its own line.

2. Step 2: Identify when semicolons are necessary

   Semicolons are needed only to separate multiple statements on the same line.

3. Final Answer:

   Only when multiple statements are on the same line -> Option D

4. Quick Check:

   Semicolons required = multiple statements on one line [OK]

Hint: Semicolons separate statements on the same line only [OK]

Common Mistakes:

• Thinking semicolons are always required
• Believing semicolons are needed after every statement
• Assuming semicolons are never used

2. Which of the following Swift code snippets is syntactically correct?

easy

A. let a = 5; let b = 10;

B. let a = 5 let b = 10;

C. let a = 5; let b = '10'

D. let a = 5 let b = 10

Solution

1. Step 1: Check semicolon usage on same line

   When two statements are on the same line, they must be separated by a semicolon.

2. Step 2: Verify each option

   let a = 5; let b = 10; correctly uses a semicolon between two statements on the same line.

3. Final Answer:

   let a = 5; let b = 10; -> Option A

4. Quick Check:

   Multiple statements same line = semicolon needed [OK]

Hint: Use semicolons only to separate statements on the same line [OK]

Common Mistakes:

• Omitting semicolon between statements on the same line
• Adding semicolons unnecessarily at line ends
• Confusing semicolon placement with other languages

3. What is the output of this Swift code?

let x = 3; let y = 4
print(x + y)

medium

A. Syntax error

B. 34

C. 7

D. Runtime error

Solution

1. Step 1: Analyze semicolon usage

   The semicolon separates two statements on the same line, which is valid in Swift.

2. Step 2: Calculate the print output

   x is 3 and y is 4, so x + y equals 7, which is printed.

3. Final Answer:

   7 -> Option C

4. Quick Check:

   3 + 4 = 7 [OK]

Hint: Semicolons separate statements; addition works normally [OK]

Common Mistakes:

• Thinking semicolon causes syntax error
• Confusing concatenation with addition
• Expecting runtime error due to semicolon

4. Identify the error in this Swift code:

let a = 10 let b = 20
print(a + b)

medium

A. Variable names are invalid

B. Missing semicolon between statements on the same line

C. Missing parentheses in print statement

D. No error, code runs fine

Solution

1. Step 1: Check statement separation

   Two statements are on the same line without a semicolon separating them, which is invalid in Swift.

2. Step 2: Confirm print syntax and variable names

   Print statement and variable names are correct; only missing semicolon causes error.

3. Final Answer:

   Missing semicolon between statements on the same line -> Option B

4. Quick Check:

   Multiple statements same line need semicolon [OK]

Hint: Add semicolon between statements on the same line [OK]

Common Mistakes:

• Ignoring missing semicolon error
• Assuming print needs no parentheses
• Thinking variable names cause error

5. You want to write two Swift statements on the same line: let name = "Alice" and print(name). Which is the correct way to write this?

hard

A. let name = "Alice"; print(name)

B. let name = 'Alice'; print(name);

C. let name = "Alice" print(name);

D. let name = "Alice" print(name)

Solution

1. Step 1: Understand semicolon use on same line

   When writing multiple statements on the same line, separate them with a semicolon.

2. Step 2: Check each option for correctness

   let name = "Alice"; print(name) correctly separates the two statements with a semicolon and omits unnecessary semicolon at the end.

3. Final Answer:

   let name = "Alice"; print(name) -> Option A

4. Quick Check:

   Separate statements on one line with semicolon [OK]

Hint: Use one semicolon between statements on the same line [OK]

Common Mistakes:

• Omitting semicolon between statements
• Adding extra semicolon after last statement unnecessarily
• Writing statements without separation