Why strong typing matters in C# - Challenge Your Understanding

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of implicit typing with var

What is the output of this C# code snippet?

C Sharp (C#)

var x = 5;
var y = "10";
var z = x + int.Parse(y);
Console.WriteLine(z);

A 510

B 15

C Compilation error

D Runtime error

💡 Hint

Remember that var infers the type at compile time and int.Parse converts string to int.

The variable x is an int with value 5, y is a string "10". int.Parse(y) converts "10" to 10. Adding 5 + 10 results in 15.

❓ Predict Output

intermediate

Effect of strong typing on method overloading

What will be the output of this C# program?

C Sharp (C#)

void PrintType(int x) => Console.WriteLine("int");
void PrintType(object x) => Console.WriteLine("object");

PrintType(5);

A Runtime error

B object

C int

D Compilation error

💡 Hint

Method overloading resolution prefers the most specific type.

The method PrintType(int) is more specific than PrintType(object), so it is chosen for an int argument.

🔧 Debug

advanced

Identify the type error in this code

This code snippet causes a compile-time error. What is the cause?

C Sharp (C#)

int x = "100";
Console.WriteLine(x);

A Cannot implicitly convert type 'string' to 'int'

B Missing semicolon

C Variable x is not initialized

D Console.WriteLine requires a string argument

💡 Hint

Check the assignment of a string to an int variable.

You cannot assign a string directly to an int variable without conversion, causing a compile-time type error.

❓ Predict Output

advanced

Result of casting with strong typing

What is the output of this C# code?

C Sharp (C#)

object obj = 42;
int num = (int)obj;
Console.WriteLine(num + 8);

A 50

B Runtime InvalidCastException

C Compilation error

D 42 8

💡 Hint

Casting from object to int is allowed if the object actually holds an int.

The object obj holds an int 42, so casting to int succeeds. Adding 8 results in 50.

🧠 Conceptual

expert

Why does strong typing prevent certain bugs?

Which of the following best explains why strong typing in C# helps prevent bugs?

A It disables type checking to improve performance.

B It allows variables to change type dynamically during execution, making the code flexible.

C It automatically converts all types to strings to avoid errors.

D It forces variables to have a fixed type, catching type mismatches at compile time before running the program.

💡 Hint

Think about when type errors are detected in strongly typed languages.

Strong typing means variables have fixed types, so the compiler can detect mismatches early, preventing many runtime errors.