Добавлено задание с длинной арифметикой

1 files changed, 70 insertions, 0 deletions

diff --git a/sem2/src/mpn.rs b/sem2/src/mpn.rs
new file mode 100644
index 0000000..27f94e0
--- /dev/null
+++ b/sem2/src/mpn.rs
@@ -0,0 +1,70 @@
+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,
+        };
+    }
+}