Quartz 4

Arithmetic Overflow

1 min read

  • C# numeric types (int, byte, etc.) have fixed sizes.

  • If you try to store a value outside their range → overflow happens.

Example:

int x = int.MaxValue; // 2,147,483,647 x = x + 1; // Overflow! Console.WriteLine(x); // -2,147,483,648 (wraps around)

By default, C# doesn’t throw an error — it just wraps around (like circular numbers).

📌 checked

checked tells C# → throw an exception if overflow occurs.

try
{
    int x = int.MaxValue;
    int y = checked(x + 1); // throws OverflowException
}
catch (OverflowException ex)
{
    Console.WriteLine("Overflow detected!");
}

Or use a block:

checked 
{     
	int x = int.MaxValue;     
	int y = x + 1;  // throws OverflowException 
}

📌 unchecked

unchecked tells C# → ignore overflow, allow wrapping (the default behavior in most cases).

unchecked
{
    int x = int.MaxValue;
    int y = x + 1;  // wraps to -2,147,483,648
    Console.WriteLine(y);
}

📌 Use Cases

  • checked → when precision matters (financial, scientific calculations).

  • unchecked → when you deliberately want wrapping (e.g., low-level bitwise operations, performance-sensitive code).

✅ Summary

  • checked → throws error on overflow.

  • unchecked → ignores overflow (wraps around).

  • You can use them as expressions or blocks.

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