feat: add fibonacci benchmark

Author: not-matthias

examples/google_benchmark_bazel/fibonacci_bench.hpp

@@ -0,0 +1 @@
+../google_benchmark_cmake/fibonacci_bench.hpp

examples/google_benchmark_cmake/fibonacci_bench.hpp

@@ -0,0 +1,38 @@
+#pragma once
+
+#include <benchmark/benchmark.h>
+
+static uint64_t fibonacci_recursive(int n) {
+  if (n <= 1) return n;
+  return fibonacci_recursive(n - 1) + fibonacci_recursive(n - 2);
+}
+
+static void BM_FibonacciRecursive(benchmark::State& state) {
+  int n = static_cast<int>(state.range(0));
+  for (auto _ : state) {
+    uint64_t result = fibonacci_recursive(n);
+    benchmark::DoNotOptimize(result);
+  }
+}
+BENCHMARK(BM_FibonacciRecursive)->Arg(35)->MinTime(5);
+
+static uint64_t fibonacci_iterative(int n) {
+  if (n <= 1) return n;
+
+  uint64_t a = 0, b = 1;
+  for (int i = 2; i <= n; ++i) {
+    uint64_t c = a + b;
+    a = b;
+    b = c;
+  }
+  return b;
+}
+
+static void BM_FibonacciIterative(benchmark::State& state) {
+  int n = static_cast<int>(state.range(0));
+  for (auto _ : state) {
+    uint64_t result = fibonacci_iterative(n);
+    benchmark::DoNotOptimize(result);
+  }
+}
+BENCHMARK(BM_FibonacciIterative)->Arg(50);

examples/google_benchmark_cmake/main.cpp

@@ -2,6 +2,7 @@
 
 #include <cstring>
 
+#include "fibonacci_bench.hpp"
 #include "fixture_bench.hpp"
 #include "sleep_bench.hpp"
 #include "template_bench.hpp"