1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
use super::*;
impl Display for MultiplicationSteps {
fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
let max_indent = self.max_digits() + 2;
let a = self.lhs.to_str_radix(self.base);
let b = self.rhs.to_str_radix(self.base);
let r = self.result.to_str_radix(self.base);
writeln!(f, "{space}{}", a, space = " ".repeat(max_indent - a.len() + 2))?;
writeln!(f, " ×{space}{}", b, space = " ".repeat(max_indent - b.len()))?;
writeln!(f, "{}", "-".repeat(max_indent + 3))?;
for (i, add) in self.steps.iter().enumerate() {
if i == 0 {
writeln!(f, "{}", add.pretty_format(max_indent, " = ", self.base))?;
}
else {
writeln!(f, "{}", add.pretty_format(max_indent, " + ", self.base))?;
}
}
writeln!(f, "{}", "-".repeat(max_indent + 3))?;
write!(f, " ={space}{result}", space = " ".repeat(2), result = r)
}
}
impl MultiplicationSteps {
pub fn new(a: &BigInt, b: &BigInt) -> MultiplicationSteps {
Self { lhs: a.clone(), rhs: b.clone(), steps: vec![], result: a.mul(b), base: 10 }
}
pub fn with_base(mut self, base: u32) -> Self {
self.base = base;
self
}
pub fn push_step(&mut self, step: ShiftAdd) {
self.steps.push(step);
}
pub fn max_digits(&self) -> usize {
self.steps.iter().map(|x| x.count_digits(self.base)).max().unwrap_or(0)
}
}