naive and memoized fibonacci

recursion/fibonacci.c

@@ -0,0 +1,66 @@
+/****************************************************************
+* File name     : memoized_fibonacci.c
+* Purpose       :
+* Author        : Linda J
+* Creation date : 10-09-2021
+* Last modified : Friday 10 September 2021 07:00:50 PM
+****************************************************************/
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+#define DEBUG
+#define FATAL    (1)
+#define ERR      (2)
+#define WARN     (3)
+#define INFO     (4)
+#define DBG      (5)
+#define CHK      (6)
+#define USR      (7)
+
+unsigned int  debug_level = USR;
+#ifdef DEBUG
+#define printd(level, ...) (level >= debug_level) ? printf(__VA_ARGS__) : 0
+#else
+#define printd(level, ...)
+#endif
+
+unsigned int memoized_fib(unsigned int n);
+unsigned int naive_fib(unsigned int n);
+
+unsigned int naive_fib(unsigned int n) {
+  if (n <= 0)
+    return 1;
+  else if (n == 1)
+    return 1;
+  else {
+    if ((n - 2) >= 0)
+      return naive_fib(n - 1) + naive_fib(n - 2);
+  }
+}
+
+//memoized
+unsigned int memoized_fib(unsigned int n) {
+  unsigned int fib[n];
+
+  fib[0] = 1;
+  fib[1] = 1;
+
+  for (unsigned int i = 2; i <= n ; i++) {
+    fib[i] = fib[i -1] + fib[i - 2]; 
+  }
+
+  return fib[n];
+}
+
+int main(unsigned int argc, char *argv[], char *envp[]) {
+  unsigned int n;
+  printd(USR, "\tfibonacci\n\n");
+
+  for(unsigned int i = 1; i < argc; i++) {
+    n = atoi(argv[i]);
+    printf("memoized_fib(%d) = %d\n", n, memoized_fib(n));
+    printf("native_fib(%d) = %d\n", n, naive_fib(n));
+  }
+  return 0;
+}