Type conversion and casting in C Sharp (C#) - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of implicit and explicit conversions

What is the output of the following C# code?

C Sharp (C#)

int a = 100;
long b = a;
int c = (int)b;
Console.WriteLine(c);

A 100

B 0

C Compilation error

D OverflowException at runtime

💡 Hint

Implicit conversion from int to long is safe; explicit cast back to int is valid here.

The int value 100 is implicitly converted to long without data loss. Casting back to int recovers the original value.

❓ Predict Output

intermediate

Result of casting double to int

What is the output of this C# code snippet?

C Sharp (C#)

double d = 9.99;
int i = (int)d;
Console.WriteLine(i);

A 10

B 9

C 9.99

D Compilation error

💡 Hint

Casting from double to int truncates the decimal part.

Casting double to int drops the fractional part, so 9.99 becomes 9.

❓ Predict Output

advanced

Behavior of unchecked overflow in casting

What will be printed by this C# code?

C Sharp (C#)

byte b = 255;
int i = b + 1;
byte c = (byte)i;
Console.WriteLine(c);

A OverflowException

B 256

C 255

D 0

💡 Hint

Casting int to byte truncates higher bits without exception in unchecked context.

Adding 1 to 255 gives 256, which cast to byte wraps around to 0 due to overflow.

❓ Predict Output

advanced

Casting reference types and invalid cast exception

What happens when this C# code runs?

C Sharp (C#)

object obj = "hello";
int num = (int)obj;
Console.WriteLine(num);

A InvalidCastException at runtime

B 0

C hello

D Compilation error

💡 Hint

Casting object holding a string to int is invalid.

The cast tries to convert a string object to int, which is not allowed and throws an exception.

❓ Predict Output

expert

Output of custom conversion operator

Given the following code, what is the output?

C Sharp (C#)

class Temperature {
    public double Celsius { get; set; }
    public static explicit operator int(Temperature t) {
        return (int)(t.Celsius * 9 / 5 + 32);
    }
}

Temperature temp = new Temperature { Celsius = 25 };
int fahrenheit = (int)temp;
Console.WriteLine(fahrenheit);

A Compilation error due to missing implicit operator

B 25

C 77

D Runtime error

💡 Hint

The explicit operator converts Celsius to Fahrenheit as int.

The explicit cast uses the operator to convert 25 Celsius to 77 Fahrenheit.