String is a value type behavior in Swift - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Swift code with strings?

Consider this Swift code where a string is assigned and then modified. What will be printed?

Swift

var greeting = "Hello"
var copy = greeting
greeting += ", world!"
print(copy)

A Compilation error

B "Hello, world!"

C "Hello"

D "world!"

💡 Hint

Remember that strings in Swift are value types, so copying creates a new independent value.

Strings in Swift are value types. When you assign greeting to copy, it copies the value. Changing greeting later does not affect copy. So copy remains "Hello".

❓ Predict Output

intermediate

What happens when you modify a copied string?

What will this Swift code print?

Swift

let original = "Swift"
var copy = original
copy.append(" Lang")
print(original)

A "Lang"

B "Swift Lang"

C Runtime error

D "Swift"

💡 Hint

Think about whether modifying copy changes original.

Since strings are value types, copy is a separate copy. Modifying copy does not affect original. So original stays "Swift".

🔧 Debug

advanced

Why does this code print two different strings?

Examine this Swift code. Why does it print two different strings?

Swift

var s1 = "Hi"
var s2 = s1
s2 = "Hello"
print(s1)
print(s2)

A Because strings are value types, s1 and s2 are independent copies.

B Because strings are reference types, s1 and s2 point to the same data.

C Because s2 was not assigned properly, it defaults to s1.

D Because print statements are delayed and show old values.

💡 Hint

Think about how value types behave when assigned and changed.

Strings in Swift are value types. Assigning s1 to s2 copies the value. Changing s2 does not affect s1. So printing s1 shows "Hi" and s2 shows "Hello".

🧠 Conceptual

advanced

Which statement about Swift strings is true?

Choose the correct statement about Swift strings and value type behavior.

A Modifying a copied string changes the original string.

B Assigning a string to a new variable creates a separate copy.

C Strings are reference types and share the same memory by default.

D Strings cannot be copied or assigned to new variables.

💡 Hint

Recall how value types behave on assignment.

Swift strings are value types. Assigning a string to a new variable copies the value, creating a separate instance. Modifying one does not affect the other.

❓ Predict Output

expert

What is the output of this Swift code with string mutation and copying?

Analyze this Swift code and determine what it prints.

Swift

var a = "Start"
var b = a
b += " End"
print(a)
print(b)

A "Start"\n"Start End"

B "Start End"\n"Start End"

C Compilation error

D "Start"\n"Start"

💡 Hint

Remember that strings are copied on assignment and changes to one do not affect the other.

Variable b is a copy of a. Appending " End" to b does not change a. So a prints "Start" and b prints "Start End".