Python Coding challenge - Day 740| What is the output of the following Python Code?

 

Code Explanation:

1. Import the Decimal class

from decimal import Decimal

The decimal module provides the Decimal class for high-precision arithmetic.

Unlike floating-point numbers (float), Decimal avoids most rounding errors that come from binary representation.

2. Add two Decimal numbers

a = Decimal("0.1") + Decimal("0.2")

Here, "0.1" and "0.2" are passed as strings to Decimal.

Decimal("0.1") represents exactly 0.1 in decimal.

Similarly, Decimal("0.2") is exactly 0.2.

Adding them gives Decimal("0.3") (perfect precision).

So a = Decimal("0.3").

3. Add two floats

b = 0.1 + 0.2

0.1 and 0.2 are stored as binary floating-point.

In binary, 0.1 and 0.2 cannot be represented exactly.

When added, the result is actually 0.30000000000000004.

So b ≈ 0.30000000000000004, not exactly 0.3.

4. Compare the values

print(a == Decimal("0.3"), b == 0.3)

First comparison:

a == Decimal("0.3") → Decimal("0.3") == Decimal("0.3") →  True.

Second comparison:

b == 0.3 → 0.30000000000000004 == 0.3 → ❌ False (due to floating-point error).

5. Final Output

True False

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