Initial data commit

Task/Digital-root/Rust/digital-root.rust

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+fn sum_digits(mut n: u64, base: u64) -> u64 {
+    let mut sum = 0u64;
+    while n > 0 {
+        sum = sum + (n % base);
+        n = n / base;
+    }
+    sum
+}
+
+// Returns tuple of (additive-persistence, digital-root)
+fn digital_root(mut num: u64, base: u64) -> (u64, u64) {
+    let mut pers = 0;
+    while num >= base {
+        pers = pers + 1;
+        num = sum_digits(num, base);
+    }
+    (pers, num)
+}
+
+fn main() {
+
+    // Test base 10
+    let values = [627615u64, 39390u64, 588225u64, 393900588225u64];
+    for &value in values.iter() {
+        let (pers, root) = digital_root(value, 10);
+        println!("{} has digital root {} and additive persistance {}",
+                 value,
+                 root,
+                 pers);
+    }
+
+    println!("");
+
+    // Test base 16
+    let values_base16 = [0x7e0, 0x14e344, 0xd60141, 0x12343210];
+    for &value in values_base16.iter() {
+        let (pers, root) = digital_root(value, 16);
+        println!("0x{:x} has digital root 0x{:x} and additive persistance 0x{:x}",
+                 value,
+                 root,
+                 pers);
+    }
+}