From 8b360ab9fc9d5f3a06dbc74bc8f81d26f07b9ba9 Mon Sep 17 00:00:00 2001
From: Amar Mahmutbegovic <amar.mahmutbegovic@gmail.com>
Date: Wed, 2 Apr 2025 23:02:38 +0200
Subject: [PATCH] add Chapter03

---
 Chapter03/google_test_example.cpp | 91 +++++++++++++++++++++++++++++++
 Chapter03/out_of_bound.cpp        |  7 +++
 Chapter03/uninitialized_value.cpp | 13 +++++
 3 files changed, 111 insertions(+)
 create mode 100644 Chapter03/google_test_example.cpp
 create mode 100644 Chapter03/out_of_bound.cpp
 create mode 100644 Chapter03/uninitialized_value.cpp

diff --git a/Chapter03/google_test_example.cpp b/Chapter03/google_test_example.cpp
new file mode 100644
index 0000000..fa050a9
--- /dev/null
+++ b/Chapter03/google_test_example.cpp
@@ -0,0 +1,91 @@
+#include <array>
+
+#include <cstdio>
+
+#include "gtest/gtest.h"
+
+template <class T, std::size_t N> struct ring_buffer {
+
+  std::array<T, N> arr;
+
+  std::size_t write_idx = 0;
+
+  std::size_t read_idx = 0;
+
+  std::size_t count = 0;
+
+  void push(T t) {
+
+    arr.at(write_idx) = t;
+
+    write_idx = (write_idx + 1) % N;
+
+    if (count < N) {
+
+      count++;
+
+    } else {
+
+      read_idx = (read_idx + 1) % N;
+    }
+  }
+
+  T pop() {
+
+    if (count == 0) {
+
+      return T{};
+    }
+
+    T value = arr.at(read_idx);
+
+    read_idx = (read_idx + 1) % N;
+
+    --count;
+
+    return value;
+  }
+
+  bool is_empty() const { return count == 0; }
+
+  std::size_t get_count() const { return count; }
+};
+
+TEST(RingBufferInt, PushPop) {
+
+  ring_buffer<int, 2> rb;
+
+  rb.push(1);
+
+  rb.push(2);
+
+  EXPECT_EQ(rb.pop(), 1);
+
+  EXPECT_EQ(rb.pop(), 2);
+}
+
+TEST(RingBufferInt, GetCount) {
+
+  ring_buffer<int, 20> rb;
+
+  for (int i = 0; i < 50; i++) {
+
+    rb.push(i);
+  }
+
+  EXPECT_EQ(rb.get_count(), 20);
+
+  for (int i = 0; i < 10; i++) {
+
+    rb.pop();
+  }
+
+  EXPECT_EQ(rb.get_count(), 10);
+}
+
+int main() {
+
+  testing::InitGoogleTest();
+
+  return RUN_ALL_TESTS();
+}
diff --git a/Chapter03/out_of_bound.cpp b/Chapter03/out_of_bound.cpp
new file mode 100644
index 0000000..c5efbc6
--- /dev/null
+++ b/Chapter03/out_of_bound.cpp
@@ -0,0 +1,7 @@
+#include <array> 
+
+int main() {
+    std::array<int, 4> arr{1, 2, 3, 4};
+
+    return arr[4];
+}
diff --git a/Chapter03/uninitialized_value.cpp b/Chapter03/uninitialized_value.cpp
new file mode 100644
index 0000000..3c4b6c0
--- /dev/null
+++ b/Chapter03/uninitialized_value.cpp
@@ -0,0 +1,13 @@
+#include <array> 
+
+int sum(const std::array<int, 4> &arr) { 
+
+    int ret; 
+
+    for(int elem: arr) { 
+        ret += elem; 
+    } 
+
+    return ret; 
+
+}