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use std::cmp::max;
use std::fmt;
use std::ops::Add;
pub struct Number {
radix: usize,
digits: Vec<u8>,
}
impl Number {
pub fn parse(snum: &str) -> Result<Number, &str> {
let radix = 10_usize;
let snum = snum.as_bytes();
let mut digits = Vec::new();
for i in (0..snum.len()).rev() {
let digit = snum[i] - '0' as u8;
if digit as usize >= radix {
return Err("Аргумент не является числом");
} else {
digits.push(digit);
}
}
return Ok(Number { radix, digits });
}
pub fn len(&self) -> usize {
self.digits.len()
}
}
impl fmt::Display for Number {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
for i in (0..self.digits.len()).rev() {
write!(f, "{}", self.digits[i])?;
}
return Ok(());
}
}
impl Add for Number {
type Output = Self;
fn add(self, other: Self) -> Self::Output {
let mut k = 0;
let len = max(self.len(), other.len());
let mut digits = Vec::new();
for i in 0..len {
let mut digit = 0;
if i < self.len() {
digit += self.digits[i] as usize;
}
if i < other.len() {
digit += other.digits[i] as usize;
}
digit += k;
let (div, rem) = (digit / self.radix, digit % self.radix);
digit = rem;
k = div;
digits.push(digit as u8);
}
if k != 0 {
digits.push(k as u8);
}
return Number {
radix: self.radix,
digits,
};
}
}
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