From db6e9bac370093b13cfb6f0b81ac066fed64b004 Mon Sep 17 00:00:00 2001
From: Martin Ashby <martin@ashbysoft.com>
Date: Wed, 16 Nov 2022 19:17:08 +0000
Subject: Messing around replacing loops with recursion leveraging
 __attribute__((musttail)) in order to avoid stack overflow

---
 fib.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 fib.c

(limited to 'fib.c')

diff --git a/fib.c b/fib.c
new file mode 100644
index 0000000..6f510c2
--- /dev/null
+++ b/fib.c
@@ -0,0 +1,35 @@
+#include <stdio.h>
+
+static long fib_internal(int n, long a, long b) {
+    if (n == 0) {
+        return a;
+    } else if (n == 1) {
+        return b;
+    } else {
+        __attribute__((musttail))
+        return fib_internal(n-1, b, a + b);
+    }
+}
+
+long fib(int n) {
+    return fib_internal(n, 0, 1);
+}
+
+void test(int n) {
+    printf("fib [%d] = [%ld]\n", n, fib(n));
+}
+
+// static long recursion_depth(long n, long max) {
+//     if (n >= max) {
+//         return n;
+//     }
+//     __attribute__((musttail))
+//     return recursion_depth(n+1, max);
+// }
+
+int main(void) {
+    for (int i=1; i<300; i++) {
+        test(i);
+    }
+    //printf("%ld\n", recursion_depth(0, 1000000000));
+}
\ No newline at end of file
-- 
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