Print function for output in Swift - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the print() function do in Swift?

The print() function shows text or values on the screen (console). It helps you see results or messages while your program runs.

beginner

How do you print a simple message like "Hello, world!" in Swift?

Use print("Hello, world!"). This tells the program to show the words Hello, world! on the screen.

beginner

Can you print numbers using print() in Swift? How?

Yes! You can print numbers directly like print(123). It will show the number 123 on the screen.

beginner

How do you print multiple values or variables in one print() statement?

You can separate values with commas, like print("Age:", age). Swift prints them with spaces between.

intermediate

What is the difference between print() and debugPrint() in Swift?

print() shows user-friendly output. debugPrint() shows more detailed info, useful for debugging your code.

Which Swift code prints the message "Welcome!" to the screen?

A echo "Welcome!"

B print("Welcome!")

C console.log("Welcome!")

D System.out.println("Welcome!")

In Swift, print() is used to show messages on the screen.

What will print(5 + 3) output in Swift?

A 8

B "5 + 3"

C 5 + 3

D Error

Swift calculates 5 + 3 and prints the result 8.

How do you print two variables, name and age, separated by a space?

A print(name + age)

B print(name.age)

C print(name & age)

D print(name, age)

Using commas in print() prints values separated by spaces.

Which function shows more detailed info for debugging in Swift?

A println()

B print()

C debugPrint()

D showDebug()

debugPrint() gives detailed output useful for debugging.

What happens if you write print() with no arguments?

A Prints an empty line

B Prints 'nil'

C Causes an error

D Prints '0'

Calling print() without arguments prints a blank line.

Explain how to use the print() function in Swift to show messages and variables.

Think about how you tell a friend what you want to show on the screen.

Describe the difference between print() and debugPrint() in Swift and when to use each.

One is for normal messages, the other helps find problems.

Practice

1.

What does the print function do in Swift?

easy

A. It shows text or values on the screen.

B. It saves data to a file.

C. It creates a new variable.

D. It deletes a program.

Solution

1. Step 1: Understand the purpose of print

   The print function is used to display output on the screen, such as text or variable values.

2. Step 2: Compare options with print's function

   Only It shows text or values on the screen. describes showing text or values on the screen, which matches print's purpose.

3. Final Answer:

   It shows text or values on the screen. -> Option A

4. Quick Check:

   print function = display output [OK]

Hint: Remember: print means show on screen [OK]

Common Mistakes:

• Thinking print saves data
• Confusing print with variable creation
• Assuming print deletes data

2.

Which of the following is the correct way to print the text Hello, Swift! in Swift?

?

easy

A. echo "Hello, Swift!"

B. println('Hello, Swift!')

C. print("Hello, Swift!")

D. print Hello, Swift!

Solution

1. Step 1: Identify correct Swift print syntax

   Swift uses print() with double quotes for strings.

2. Step 2: Check each option

   print("Hello, Swift!") uses print("Hello, Swift!"), which is correct. Others use wrong functions or missing parentheses/quotes.

3. Final Answer:

   print("Hello, Swift!") -> Option C

4. Quick Check:

   Correct print syntax = print("Hello, Swift!") [OK]

Hint: Use print() with double quotes for text [OK]

Common Mistakes:

• Using single quotes for strings
• Missing parentheses
• Using wrong function names

3.

What will be the output of this Swift code?

let name = "Anna"
print("Hello, \(name)!")

medium

A. Error: Invalid syntax

B. Hello, \(name)!

C. Hello, name!

D. Hello, Anna!

Solution

1. Step 1: Understand string interpolation

   The syntax \(name) inserts the value of variable name into the string.

2. Step 2: Substitute variable value

   Since name is "Anna", the printed string becomes "Hello, Anna!".

3. Final Answer:

   Hello, Anna! -> Option D

4. Quick Check:

   String interpolation = Hello, Anna! [OK]

Hint: Use \(variable) to insert values in strings [OK]

Common Mistakes:

• Printing variable name literally
• Forgetting \( ) syntax
• Syntax errors in string interpolation

4.

Find the error in this Swift code snippet:

let age = 25
print("Age is: " + age)

medium

A. Missing parentheses in print.

B. Cannot add String and Int directly.

C. Variable age is not declared.

D. print function is misspelled.

Solution

1. Step 1: Analyze the print statement

   The code tries to add a String and an Int using +, which is not allowed in Swift.

2. Step 2: Identify correct way to combine String and Int

   Use string interpolation like "Age is: \(age)" instead of + operator.

3. Final Answer:

   Cannot add String and Int directly. -> Option B

4. Quick Check:

   String + Int needs interpolation [OK]

Hint: Use \(variable) to combine text and numbers [OK]

Common Mistakes:

• Trying to add String and Int
• Missing string interpolation
• Assuming + works for different types

5.

You want to print a list of numbers from 1 to 3 on the same line separated by spaces using Swift. Which code will do this correctly?

?

hard

A. print(1, 2, 3, separator: " ")

B. print("1, 2, 3")

C. print(1 + " " + 2 + " " + 3)

D. print(1, 2, 3, sep: " ")

Solution

1. Step 1: Understand print's separator parameter

   Swift's print can take multiple values and a separator argument to join them with a string.

2. Step 2: Check each option

   print(1, 2, 3, separator: " ") uses separator: " " correctly to print "1 2 3". Adding numbers and strings causes type error, print("1, 2, 3") prints commas instead of spaces, wrong parameter name fails.

3. Final Answer:

   print(1, 2, 3, separator: " ") -> Option A

4. Quick Check:

   Use separator: " " to join values [OK]

Hint: Use separator: " " to print values with spaces [OK]

Common Mistakes:

• Using wrong parameter name sep
• Trying to add Int and String
• Printing fixed string instead of variables