Task

Write a function/procedure/subroutine that is called with an integer value and returns the middle three digits of the integer if possible or a clear indication of an error if this is not possible.

Note: The order of the middle digits should be preserved.

Your function should be tested with the following values; the first line should return valid answers, those of the second line should return clear indications of an error:

123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345
1, 2, -1, -10, 2002, -2002, 0

Show your output on this page.




package m3
 
import (
    "errors"
    "strconv"
)
 
var (
    ErrorLT3  = errors.New("N of at least three digits required.")
    ErrorEven = errors.New("N with odd number of digits required.")
)
 
func Digits(i int) (string, error) {
    if i < 0 {
        i = -i
    }
    if i < 100 {
        return "", ErrorLT3
    }
    s := strconv.Itoa(i)
    if len(s)%2 == 0 {
        return "", ErrorEven
    }
    m := len(s) / 2
    return s[m-1 : m+2], nil
}