String interpolation in C Sharp (C#) - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of simple string interpolation

What is the output of this C# code using string interpolation?

C Sharp (C#)

int apples = 5;
int oranges = 3;
string result = $"I have {apples} apples and {oranges} oranges.";
Console.WriteLine(result);

A I have 5 apples and 3 oranges.

B I have {apples} apples and {oranges} oranges.

C I have apples oranges.

D I have 8 apples and oranges.

💡 Hint

Look at how variables inside curly braces are replaced by their values.

The $ symbol before the string allows variables inside { } to be replaced by their values. So {apples} becomes 5 and {oranges} becomes 3.

❓ Predict Output

intermediate

Output with expression inside interpolation

What will this C# code print?

C Sharp (C#)

int x = 4;
int y = 7;
Console.WriteLine($"Sum is {x + y}");

A Sum is 47

B Sum is x + y

C Sum is {x + y}

D Sum is 11

💡 Hint

Inside { }, you can put expressions, not just variables.

The expression x + y is evaluated to 11 and inserted into the string.

❓ Predict Output

advanced

Output with format specifier in interpolation

What is the output of this C# code?

C Sharp (C#)

double price = 1234.5678;
Console.WriteLine($"Price: {price:F2}");

A Price: 1234.5678

B Price: 1234.57

C Price: {price:F2}

D Price: 1234.5

💡 Hint

The :F2 means format the number with 2 decimal places.

The format specifier F2 rounds the number to 2 decimal places.

❓ Predict Output

advanced

Output with nested interpolation and escape sequences

What will this C# code print?

C Sharp (C#)

string name = "Anna";
int age = 30;
Console.WriteLine($"Name: {name}, Age: {age}\nWelcome!");

A Name: Anna, Age: 30 Welcome!

B Name: Anna, Age: 30\nWelcome!

C

Name: Anna, Age: 30
Welcome!

D Name: {name}, Age: {age}\nWelcome!

💡 Hint

The \n is a newline character and will create a line break.

The \n creates a new line after Age: 30, so Welcome! appears on the next line.

🧠 Conceptual

expert

Understanding string interpolation with null values

What is the output of this C# code snippet?

C Sharp (C#)

string? city = null;
Console.WriteLine($"City: {city ?? "Unknown"}");

A City: Unknown

B City: {city ?? "Unknown"}

C City: null

D City:

💡 Hint

The ?? operator returns the right side if the left side is null.

Since city is null, the expression city ?? "Unknown" evaluates to "Unknown".