diff --git a/examples/chapter11_07/target/micros/avr/startup/int_vect.cpp b/examples/chapter11_07/target/micros/avr/startup/int_vect.cpp
index b408d9438..d1aa12b9e 100644
--- a/examples/chapter11_07/target/micros/avr/startup/int_vect.cpp
+++ b/examples/chapter11_07/target/micros/avr/startup/int_vect.cpp
@@ -5,15 +5,16 @@
 //  or copy at http://www.boost.org/LICENSE_1_0.txt)
 //
 
-#include <array>
-#include <cstdint>
+#include <FreeRTOS.h>
 #include <mcal_cpu.h>
 
-#include <FreeRTOS.h>
+#include <array>
+#include <cstddef>
+#include <cstdint>
 
 extern "C" void __my_startup       () __attribute__((section(".startup"), used, noinline));
 extern "C" void __vector_unused_irq() __attribute__((signal, used, externally_visible));
-#if configUSE_PREEMPTION == 1
+#if (defined(configUSE_PREEMPTION) && (configUSE_PREEMPTION == 1))
 extern "C" void __vector_11        () __attribute__((signal, used, externally_visible, naked));
 #else
 extern "C" void __vector_11        () __attribute__((signal, used, externally_visible));
@@ -31,21 +32,21 @@ void __vector_unused_irq()
 
 namespace
 {
-  typedef struct struct_isr_type
+  typedef struct isr_type
   {
-    typedef void(*function_type)();
+    using function_type = void(*)();
 
-    const std::uint8_t  jmp[2]; // JMP instruction (0x940C): 0x0C = low byte, 0x94 = high byte.
-    const function_type func;   // The interrupt service routine.
+    const std::uint8_t  jmp[std::size_t { UINT8_C(2) }];  // JMP instruction (0x940C): 0x0C = low byte, 0x94 = high byte.
+    const function_type func;                             // The interrupt service routine.
   }
   isr_type;
 }
 
 extern "C"
-const volatile std::array<isr_type, 26U> __isr_vector __attribute__((section(".isr_vector")));
+const volatile std::array<isr_type, std::size_t { UINT8_C(26) }> __isr_vector __attribute__((section(".isr_vector")));
 
 extern "C"
-const volatile std::array<isr_type, 26U> __isr_vector =
+const volatile std::array<isr_type, std::size_t { UINT8_C(26) }> __isr_vector =
 {{
                                               // addr.  nr. interrupt source
   { { 0x0C, 0x94 }, __my_startup },           // 0x00,  0,  reset