dec2bin function provides wrong answer

For example, when I type dec2bin(8), I expect the answer is 100b, instead the returned value in command window is actually 1000

[KALYAN ACHARJYA]

Why 100b? Its correct

dec2bin(7)

ans = '111'

dec2bin(8)

ans = '1000'

dec2bin(15)

ans = '1111'

dec2bin(20)

ans = '10100'

[Xin]

Ah! Forgot the last bit. Silly me...

Thank you for the clarification!

Answer 1

[John D'Errico]

So the binary representation of 8 is not 1000?

Let me see, 8 = 1*2^3 + 0*2^2 + 0*2^1 + 0*2^0.

I think you are mistaken.

dec2bin(8)

ans = '1000'

1*2^3 + 0*2^2 + 0*2^1 + 0*2^0

ans = 8

In fact, the number 100 in binary is the decimal 4.

1*2^2 + 0*2^1 + 0*2^0

ans = 4

Maybe you forgot about that least order (units) bit. Note that if binary numbers did not have that least order unit bit, then a binary number could never represent any odd number. And that in itself would be quite an "odd" thing.

[Xin]

Yes, indeed. Forgot about the last bit. Thank you so much for your help with this!