update main.cpp

main.cpp

@@ -3,13 +3,12 @@
 #include "mbed.h"
 #include <iostream>
 
-
 namespace ost {
     class Event {
         public:
         Event(int sourceId = -1):source{sourceId}{}
         int GetSource() {return source;}
-        virtual ~Event();
+        virtual ~Event() = default;
 
         protected:
         int source;
@@ -17,12 +16,12 @@ namespace ost {
 
     class ButtonEvent : public Event {
         public:
-        ButtonEvent();
+        ButtonEvent() = default;
     };
 
     class SystemEvent : public Event {
         public:
-        SystemEvent();
+        SystemEvent() = default;
         void SetSource(int id) {source = id;}
     };
 }
@@ -30,22 +29,38 @@ namespace ost {
 
 int main() {
     using namespace ost;
-    using ost::Event;           // required, because mbed.h (?) declares a different type "Event" in global namespace!
+    using ost::Event;               // required, because mbed.h (?) declares a different type "Event" in global namespace!
 
     constexpr double d{37.34f};
-    constexpr int ia[]{4, 5, 6};
-    int x;                      // TODO init with the integer part of d, use a type cast -- is it required?
-    float f;                    // TODO init with value of d, suppress possible warning "loss of precision", use a type cast -- is it required?
-    int *ip;                    // TODO init with address of 0-th element of ia, use a type cast -- is it required?
+    
+    int ia[]{4, 5, 6};
+
+    //int x;                        // TODO init with the integer part of d, use a type cast -- is it required?
+    int x{static_cast<int>(d)};     // not reuqired, but useful to suppress potential warning
+
+    //float f;                      // TODO init with value of d, suppress possible warning "loss of precision", use a type cast -- is it required?
+    float f{static_cast<float>(d)}; // not reuqired, but useful to suppress potential warning
+
+    //int *ip;                      // TODO init with address of 0-th element of ia, use a type cast -- is it required?
+    int *ip = ia;                   // We do not need a type cast here, implicit type conversion is perfectly fine. 
+                                    // However, using a static_cast is not wrong:
+    //int *ip = static_cast<int*>(ia);
 
     std::array<const Event*, 10> ea{new Event(10), new ButtonEvent, new SystemEvent, new Event(20), new SystemEvent};
 
     for (auto& e : ea) {
         // TODO: call SetSource(200) on all instances of type SystemEvent. You will need two type casts for this...
+        SystemEvent* sep = dynamic_cast<SystemEvent*>(const_cast<Event*>(e));   // we need dynamic_cast for finding the relevant elements as well as 
+        if (sep) { // sep will be nullptr, if dynamic_cast fails                   const_cast to temporarily modify const-ness of Event* type
+            sep->SetSource(200);
+        }
     }
 
     // print each byte of f in hex:
-    for (size_t i = sizeof(f) - 1; i >= 0; --i) {
-        printf("%hhx", static_cast<unsigned char>(0));    // TODO replace static_cast<unsigned char>(0) with correct expression. Use a type cast -- is it required?
+    printf("0x");
+    for (size_t i = sizeof(f); i-- > 0;) {
+        //printf("%hhx", static_cast<unsigned char>(0));    // TODO replace static_cast<unsigned char>(0) with correct expression. Use a type cast -- is it required?
+        printf("%hhx", reinterpret_cast<uint8_t*>(&f)[i]);  // reinterpret_cast is required here!
     }
+    printf("\r\n");
 }
\ No newline at end of file