Complete missing implementations in challenge exercise files

src/Ch02/02_13/CodeDemo.cpp

@@ -8,7 +8,7 @@
 int add_int(float a, double b, long double c){
     int result = 0;
 
-    // Write your code here
+    result = (int) a + (int) b + (int) c;
 
     return result;
 }

src/Ch03/03_08/CodeDemo.cpp

@@ -8,7 +8,7 @@
 double my_average(int a, int8_t b, uint32_t c){
     double result = 0.0;
 
-    // Write your code here
+    result = (a + b + c) / 3.0;
 
     return result;
 }

src/Ch04/04_11/CodeDemo.cpp

@@ -9,7 +9,9 @@
 std::vector<int> SelectKeyPoints(std::vector<int> distances, int checkpointIndex){
     std::vector<int> result;
 
-    // Write your code here
+    result.push_back(*distances.begin());         // Add the first element
+    result.push_back(distances[checkpointIndex]); // Add the element at checkpointIndex
+    result.push_back(distances.back());           // Add the last element
 
     return result;
 }

src/Ch05/05_09/CodeDemo.cpp

@@ -15,7 +15,18 @@ struct Resource{
 double CalculateTotalCost(std::vector<Resource> resources){
     double result = 0.0;
 
-    // Write your code here
+    for (const auto& resource : resources){
+        double costWithTax = resource.baseCost;
+
+        if (resource.type == 'B')      // Basic resource: 5% tax
+            costWithTax += resource.baseCost * 0.05;
+        else if (resource.type == 'L') // Luxury resource: 15% tax
+            costWithTax += resource.baseCost * 0.15;
+
+        // Essential resource 'E' has no tax, so no change is needed
+
+        result += costWithTax;
+    }
 
     return result;
 }

src/Ch06/06_07/CodeDemo.cpp

@@ -5,25 +5,30 @@
 #include <iostream>
 #include <cstdint>
 #include <vector>
+#include <cmath>
 
 // Function to calculate score based on milliseconds difference 
 // You still need to make the bonus multiplier optional with a default value
-double CalculateScore(int millisecondsDiff, double bonusMultiplier){
-    double score = 0.0;
+double CalculateScore(int millisecondsDiff, double bonusMultiplier = 1.0){
+    double score;
 
-    // Write your code here
-
-    return score;
+    if (std::abs(millisecondsDiff) <= 50)
+        score = 100; // Perfect
+    else if (std::abs(millisecondsDiff) <= 100)
+        score = 70;  // Good
+    else if (std::abs(millisecondsDiff) <= 200)
+        score = 50;  // Okay
+    else
+        score = 0;   // Miss
+
+    return score * bonusMultiplier; // Apply the bonus multiplier
 }
 
 // Overloaded function to calculate score based on seconds difference 
 // You still need to make the bonus multiplier optional with a default value
-double CalculateScore(double secondsDiff, double bonusMultiplier){
-    double score = 0.0;
-
-    // Write your code here
-
-    return score;
+double CalculateScore(double secondsDiff, double bonusMultiplier = 1.5){
+    int millisecondsDiff = static_cast<int>(secondsDiff * 1000); // Convert seconds to milliseconds
+    return CalculateScore(millisecondsDiff, bonusMultiplier); // Return the integer version with multiplier
 }
 
 // Function to call both overloaded functions and return a vector of results

src/Ch07/07_05b/CodeDemo.cpp

@@ -74,17 +74,26 @@ int main(){
     Inventory myInventory(5); 
 
     // Add 5 items
+    myInventory.addItem("Health Potion"); 
+    myInventory.addItem("Mana Potion");
+    myInventory.addItem("Sword");
+    myInventory.addItem("Shield");
+    myInventory.addItem("Bow");
 
     // Display current inventory
     myInventory.displayInventory(); 
 
     // Try to add another item when inventory is full
+    myInventory.addItem("Arrow");
 
     // Remove an item
+    myInventory.removeItem("Mana Potion");
 
     // Display the item count
+    std::cout << "The inventory now contains: " << myInventory.getItemCount() << " items." << std::endl;
 
     // Access item by index
+    std::cout << "Item at index 2: " << myInventory.getItem(2) << std::endl; 
 
     // Display final state of inventory
     myInventory.displayInventory();

src/Ch07/07_10/CodeDemo.cpp

@@ -9,7 +9,53 @@
 #include <utility>
 
 class Person{
-    // Write your code here
+private:
+    std::string name;
+    float energy;
+    float happiness;
+    float health;
+
+public:
+    // Constructor
+    Person(const std::string& name, float energy, float happiness, float health)
+        : name(name), energy(energy), happiness(happiness), health(health) {}
+
+    // Member function to eat
+    void Eat(float calories){
+        energy += (calories * 7.0) / 200.0;
+        if (energy > 100) energy = 100;  // Cap energy to 100
+    }
+
+    // Member function to play
+    void Play(float minutes){
+        happiness += minutes / 2.0; // Playing increases happiness by half the minutes
+        energy -= minutes / 3.0;    // Playing decreases energy proportionally
+        if (happiness > 100) happiness = 100;  // Cap happiness to 100
+        if (energy < 0) energy = 0;  // Ensure energy doesn't go below 0
+    }
+
+    // Member function to sleep
+    void Sleep(float hours){
+        energy += hours * 3.75;  // Sleeping increases energy
+        health += hours * 2.5;  // Sleeping increases health
+        if (energy > 100) energy = 100;  // Cap energy to 100
+        if (health > 100) health = 100;  // Cap health to 100
+    }
+
+    // Getter for energy
+    float GetEnergy() const{
+        return energy;
+    }
+
+    // Getter for happiness
+    float GetHappiness() const{
+        return happiness;
+    }
+
+    // Getter for health
+    float GetHealth() const{
+        return health;
+    }
 };
 
 int main(){

src/Ch08/08_10/CodeDemo.cpp

@@ -24,9 +24,26 @@ enum class Operation{
 };
 
 deque<pair<string, int>> ManagePetSchedule(const deque<pair<string, int>>& initialActivities, const vector<pair<Operation, pair<string, int>>>& operations){
-    deque<pair<string, int>> schedule;
+    deque<pair<string, int>> schedule = initialActivities;  // Initialize the schedule
 
-    // Write your code here.
+    for (const auto& op : operations){
+        switch (op.first) {
+            case Operation::ADD_FRONT:
+                schedule.push_front(op.second);
+                break;
+            case Operation::ADD_BACK:
+                schedule.push_back(op.second);
+                break;
+            case Operation::REMOVE_FRONT:
+                if (!schedule.empty())
+                    schedule.pop_front();
+                break;
+            case Operation::REMOVE_BACK:
+                if (!schedule.empty())
+                    schedule.pop_back();
+                break;
+        }
+    }
 
     return schedule;
 }