Re: [go-nuts] "Effective Go" error

[chris dollin]

What's strange about it?

["it" being: x = x*10 + int(b[i])-'0'
]

Chris

--
Chris "allusive" Dollin

[Jan Mercl]

On Thu, May 23, 2013 at 3:56 PM, Tony Hsu <gosha...@gmail.com> wrote:
> The first example in the "Function" section, there is a strange looking
> expression.

>
> x = x*10 + int(b[i])-'0'

Take the value of x. Multiply it by 10. Take the value of b at index
i. Convert it to integer. Add with the previous result. From the new
result subtract the unicode codepoint value of character '0', which is
0x30, which is 48 decadic. Put the new result into variable x.

-j

[peterGo]

Tony,

For ASCII character code (byte) digits 0 thru 9 (hexadecimal ASCII codes 0x30 though 0x39), we have

    binary(digit) = ascii(digit) - ascii(zero)

Rewrite the expression:

    x = x*10 + int(b[i])-'0'

    x = x*10 + int(b[i]-'0')

If x is int(12) and b[i] is byte('3') then, by assignment,

    x = int(12)*10+int(byte(0x33)-byte(0x30)) = int(123)

Peter

[Tony Hsu]

Thanks! The Go community is far more friendlier and helpful than I had expected.

I own a GAE service called "GoChild", but it's related to another meaning of Go:)