Getting type information at runtime in C Sharp (C#) - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of Type Name Retrieval

What is the output of this C# code snippet?

C Sharp (C#)

int number = 42;
Console.WriteLine(number.GetType().Name);

A "System.Int32"

B "int"

C "Number"

D "Int32"

💡 Hint

Use GetType() and check the Name property.

The GetType() method returns the runtime type of the object. The Name property returns the simple name of the type, which for an int is "Int32".

❓ Predict Output

intermediate

Output of Checking Type Equality

What will this code print?

C Sharp (C#)

object obj = "hello";
if (obj.GetType() == typeof(string))
    Console.WriteLine("Match");
else
    Console.WriteLine("No Match");

A Match

B No Match

C Compilation error

D Runtime exception

💡 Hint

Compare the runtime type of obj with typeof(string).

The object obj holds a string, so obj.GetType() returns System.String, which equals typeof(string).

🔧 Debug

advanced

Identify the Error in Type Checking

What error does this code produce when run?

C Sharp (C#)

object val = null;
if (val.GetType() == typeof(object))
    Console.WriteLine("Object");
else
    Console.WriteLine("Not Object");

A Prints "Not Object"

B Prints "Object"

C NullReferenceException

D Compilation error

💡 Hint

Check what happens when calling GetType() on null.

Calling GetType() on a null reference causes a NullReferenceException at runtime.

🧠 Conceptual

advanced

Understanding typeof vs GetType()

Which statement is true about typeof and GetType() in C#?

A typeof gets the compile-time type; GetType() gets the runtime type of an instance

B typeof gets the runtime type; GetType() gets the compile-time type

C Both typeof and GetType() return the same type information always

D typeof can only be used on variables; GetType() only on types

💡 Hint

Think about when you use typeof and when you call GetType().

typeof is used with a type name at compile time, while GetType() is called on an instance to get its runtime type.

❓ Predict Output

expert

Output of Type Checking with Inheritance

What is the output of this code?

C Sharp (C#)

class Animal {}
class Dog : Animal {}

Animal pet = new Dog();
Console.WriteLine(pet.GetType() == typeof(Animal));

A True

B False

C Compilation error

D Runtime exception

💡 Hint

GetType() returns the actual runtime type, not the declared type.

pet is declared as Animal but holds a Dog instance. GetType() returns Dog, which is not equal to typeof(Animal).