langs a-z

Task/Fibonacci-sequence/Rust/fibonacci-sequence-1.rust

@@ -0,0 +1,67 @@
+fn fib(n: int, f: fn (num: i64) -> bool) -> (i64, int) {
+    if n < 0 {
+        // Let these variables be mutated, otherwise too slow
+        let mut n1:i64 = 0, n2:i64 = -1, i:int = 0, tmp:i64;
+        while i > n {
+            f(n1);
+            tmp = n1-n2;
+            if (tmp > 0 && n2 > 0) { //Detect overflow
+                io::println("\nReached the limit of i64, halting");
+                return (n1, i);
+            }
+            n1 = n2;
+            n2 = tmp;
+            i -= 1;
+        }
+        (n1+n2, n)
+    } else if n > 0 {
+        // And these variables
+        let mut n1:i64 = 0, n2:i64 = 1, i:int = 0, tmp:i64;
+        while i < n {
+            f(n1);
+            tmp = n1+n2;
+            if (tmp < 0) { //Detect overflow
+                io::println("\nReached the limit of i64, halting");
+                return (n1, i);
+            }
+            n1 = n2;
+            n2 = tmp;
+            i += 1;
+        }
+        (n2-n1, n)
+    } else {
+        f(0);
+        (0,1)
+    }
+}
+
+fn main() {
+    let args = os::args();
+    let n = if args.len() == 1 {
+        10
+    } else if args.len() > 1 {
+        // Convert from a string
+        match (int::from_str(args[1])) {
+            Some(num)   => num,
+            None        => 10 //Fall back to default
+        }
+    } else {
+        /* Required to use the if as an expression.
+         * We know that args.len() is always >= 1, the compiler
+         * does not. fail lets it know that we can't get past here.
+         */
+        fail ~"No arguments given, somehow...";
+    };
+
+    /* Use the loop protocol to be able to do things
+     * with the sequence given, in this case, print them out.
+     * The loop itself returns a tuple with where it got to and
+     * what the number is.
+     */
+    let (result, n) = for fib(n) |num| {
+        //print out the sequence
+        io::print(fmt!("%? ", num));
+    };
+
+    io::println(fmt!("\nThe %dth fibonacci number is: %?", n, result));
+}

Task/Fibonacci-sequence/Rust/fibonacci-sequence-2.rust

@@ -0,0 +1,19 @@
+fn main() {
+
+   fn fib(n: int) -> int {
+
+     fn _fib(n: int, a: int, b: int) -> int {
+       match (n, a, b) {
+	 (0, _, _) => a,
+	 _         => _fib(n-1, a+b, a)
+       }
+     }
+
+     _fib(n, 0, 1)
+
+   }
+
+   for int::range(0,20) |n| {
+     io::println(fmt!("%?", fib(n)))
+   }
+}