## XOR – The Interesting Gate

*Note: The interesting features in XOR and XNOR are somehow the same but with small difference, I’ll speak in details here about XOR and will provide another article for XNOR later.*

Among other logic gates, XOR and XNOR are interesting gates having some unique features.

### Multi-input XOR

All 2-input logic gates have the same meaning when they have more than 2 inputs. For example an AND gate is a gate that outputs 1 when all its inputs are 1, an OR gate outputs 1 when any of the inputs is 1, a NAND gate outputs 0 when all its inputs are 1, a NOR gate outputs 1 when all its inputs are 0.

A 2-input XOR gate outputs 1 when there’s exactly a single 1 at the inputs which means it’s exclusively there and that’s from where the name XOR (Exclusive OR) comes. We can alternatively say that it outputs 1 when the 2 inputs are different.

A multi-input XOR gate however doesn’t necessarily have the same meaning as the 2-input XOR above. There’re two different interpretations for a multi-input XOR and let’s check that on a 3-input XOR as an example:

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