Middle three digits: Difference between revisions

=={{header|Rust}}==

<lang rust>fn middle_three_digits(x: int) -> Result<~str, ~str> {

let s = int::abs(x).to_str();

let len = s.len();

if len < 3 {

Err(~"Too short")

} else if len % 2 == 0 {

Err(~"Even number of digits")

} else {

Ok(s.slice(len/2 - 1, len/2 + 2))

}

}

fn print_result(x: int) {

io::print(fmt!("middle_three_digits(%?) returned: ", x));

match middle_three_digits(x) {

Ok(move s) => io::println(fmt!("Success, %s", s)),

Err(move s) => io::println(fmt!("Failure, %s", s))

}

}

fn main() {

let passing = [123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345];

let failing = [1, 2, -1, -10, 2002, -2002, 0];

for passing.each |i| {

print_result(*i);

}

for failing.each |i| {

print_result(*i);

}

}</lang>

Output:

<pre>middle_three_digits(123) returned: Success, 123

middle_three_digits(12345) returned: Success, 234

middle_three_digits(1234567) returned: Success, 345

middle_three_digits(987654321) returned: Success, 654

middle_three_digits(10001) returned: Success, 000

middle_three_digits(-10001) returned: Success, 000

middle_three_digits(-123) returned: Success, 123

middle_three_digits(-100) returned: Success, 100

middle_three_digits(100) returned: Success, 100

middle_three_digits(-12345) returned: Success, 234

middle_three_digits(1) returned: Failure, Too short

middle_three_digits(2) returned: Failure, Too short

middle_three_digits(-1) returned: Failure, Too short

middle_three_digits(-10) returned: Failure, Too short

middle_three_digits(2002) returned: Failure, Even number of digits

middle_three_digits(-2002) returned: Failure, Even number of digits

middle_three_digits(0) returned: Failure, Too short</pre>