Expression-bodied methods in C Sharp (C#) - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of expression-bodied method with arithmetic

What is the output of this C# code using an expression-bodied method?

C Sharp (C#)

class Calculator {
    public int Double(int x) => x * 2;
}

var calc = new Calculator();
System.Console.WriteLine(calc.Double(5));

A 25

B 5

C 10

D Compilation error

💡 Hint

Look at how the method returns the value directly using the expression-bodied syntax.

The method Double returns x multiplied by 2. For input 5, output is 10.

❓ Predict Output

intermediate

Expression-bodied property output

What will be printed by this C# program using an expression-bodied property?

C Sharp (C#)

class Person {
    public string Name { get; }
    public Person(string name) => Name = name;
    public string Greeting => $"Hello, {Name}!";
}

var p = new Person("Anna");
System.Console.WriteLine(p.Greeting);

A Hello, Anna!

B Hello, !

C Anna

D Compilation error

💡 Hint

The Greeting property uses expression-bodied syntax to return a formatted string.

The Greeting property returns "Hello, " plus the Name property value, which is "Anna".

❓ Predict Output

advanced

Expression-bodied method with conditional expression

What is the output of this C# code using an expression-bodied method with a conditional operator?

C Sharp (C#)

class NumberCheck {
    public string Check(int n) => n % 2 == 0 ? "Even" : "Odd";
}

var checker = new NumberCheck();
System.Console.WriteLine(checker.Check(7));

A 7

B Odd

C Even

D Compilation error

💡 Hint

The method returns "Even" if the number is divisible by 2, otherwise "Odd".

7 is not divisible by 2, so the method returns "Odd".

❓ Predict Output

advanced

Expression-bodied method with tuple return

What is the output of this C# code that uses an expression-bodied method returning a tuple?

C Sharp (C#)

class Point {
    public int X { get; }
    public int Y { get; }
    public Point(int x, int y) => (X, Y) = (x, y);
    public (int, int) GetCoordinates() => (X, Y);
}

var pt = new Point(3, 4);
var coords = pt.GetCoordinates();
System.Console.WriteLine($"({coords.Item1}, {coords.Item2})");

A Compilation error

B (4, 3)

C (0, 0)

D (3, 4)

💡 Hint

The method returns the tuple of X and Y properties directly.

The GetCoordinates method returns (3, 4), so the output is (3, 4).

❓ Predict Output

expert

Expression-bodied method with pattern matching and switch expression

What is the output of this C# code using an expression-bodied method with a switch expression and pattern matching?

C Sharp (C#)

class Shape {
    public string Type { get; }
    public double Size { get; }
    public Shape(string type, double size) => (Type, Size) = (type, size);
    public string Describe() => Type switch {
        "Circle" when Size > 0 => $"Circle with radius {Size}",
        "Square" when Size > 0 => $"Square with side {Size}",
        _ => "Unknown shape"
    };
}

var shape = new Shape("Circle", 5);
System.Console.WriteLine(shape.Describe());

A Circle with radius 5

B Square with side 5

C Unknown shape

D Compilation error

💡 Hint

The switch expression matches the Type and checks the Size condition.

The Type is "Circle" and Size is 5 > 0, so it returns "Circle with radius 5".