46 lines
1.3 KiB
Rust
46 lines
1.3 KiB
Rust
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use std::{
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cmp::min,
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iter::zip,
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ops::{Sub, SubAssign},
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};
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use super::{Number, Sign};
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impl Sub for Number {
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type Output = Self;
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fn sub(self, rhs: Self) -> Self::Output {
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let self_len = self.digits.len();
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let rhs_len = rhs.digits.len();
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let mut self_digits = self.digits.clone();
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let mut rhs_digits = rhs.digits.clone();
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if self_len != rhs_len {
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let difference = (self_len).abs_diff(rhs_len);
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let pad = vec![0isize; difference];
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if min(self_len, rhs_len) == self_len {
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self_digits = [pad, self.digits].concat();
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} else {
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rhs_digits = [pad, rhs.digits].concat();
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}
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}
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let zipped = zip(self_digits.iter(), rhs_digits.iter());
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let added = zipped
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.map(|(self_digit, rhs_digit)| self_digit - rhs_digit)
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.collect();
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let mut underflown_number = Self {
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digits: added,
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sign: Sign::Positif,
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};
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underflown_number.handle_underflows();
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underflown_number
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}
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}
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impl SubAssign for Number {
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fn sub_assign(&mut self, rhs: Self) {
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let new = self.clone() - rhs;
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self.digits = new.digits;
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self.sign = new.sign;
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}
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}
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