add Chapter01 examples

Chapter01/ring_buffer.cpp

@@ -0,0 +1,48 @@
+#include <array>
+#include <cstdio>
+
+template <class T, std::size_t N> struct ring_buffer {
+
+  std::array<T, N> arr;
+  std::size_t write_idx = 0; // Index of the next element to write (push)
+  std::size_t read_idx = 0;  // Index of the next element to read (pop)
+  std::size_t count = 0;     // Number of elements in the buffer
+                             //
+  void push(T t) {
+    arr.at(write_idx) = t;
+    write_idx = (write_idx + 1) % N;
+    if (count < N) {
+      count++;
+    } else {
+      // buffer is full, move forward read_idx
+      read_idx = (read_idx + 1) % N;
+    }
+  }
+
+  T pop() {
+    if (count == 0) {
+      // Buffer is empty, return a default-constructed T.
+      return T{};
+    }
+    T value = arr.at(read_idx);
+    read_idx = (read_idx + 1) % N;
+    --count;
+    return value;
+  }
+
+  bool is_empty() const { return count == 0; }
+};
+
+int main() {
+  ring_buffer<int, 5> rb;
+
+  for (int i = 0; i < 10; ++i) {
+    rb.push(i);
+  }
+
+  while (!rb.is_empty()) {
+    printf("%d\n", rb.pop());
+  }
+
+  return 0;
+}