Print function for output in Swift - Mini Project: Build & Apply

Print function for output

📖 Scenario: You want to greet your friends by printing messages on the screen.

🎯 Goal: Learn how to use the print function in Swift to show messages on the screen.

📋 What You'll Learn

Create a variable with a greeting message

Create a variable with a friend's name

Use the print function to show the greeting message

Use the print function to show a combined greeting with the friend's name

💡 Why This Matters

🌍 Real World

Printing messages is the first step in making apps that talk to users.

💼 Career

Knowing how to show output is essential for debugging and user interaction in software development.

1

Create a greeting message

Create a variable called greeting and set it to the string "Hello".

Swift

# Create a variable called greeting and set it to "Hello"
# Your code here

Hint

Use var greeting = "Hello" to create the variable.

2

Create a friend's name variable

Create a variable called friendName and set it to the string "Anna".

Swift

var greeting = "Hello"
# Create a variable called friendName and set it to "Anna"
# Your code here

Hint

Use var friendName = "Anna" to create the variable.

3

Print the greeting message

Use the print function to display the value of the variable greeting.

Swift

var greeting = "Hello"
var friendName = "Anna"
# Use print to show the greeting message
# Your code here

Hint

Use print(greeting) to show the greeting.

4

Print a combined greeting with the friend's name

Use the print function to display the combined message: "Hello, Anna!" by joining greeting and friendName with a comma and exclamation mark.

Swift

var greeting = "Hello"
var friendName = "Anna"
print(greeting)
# Use print to show "Hello, Anna!" by combining greeting and friendName
# Your code here

Hint

Use string interpolation like "\(greeting), \(friendName)!" inside print.

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