schedule

exercises/area.cpp

@@ -2,6 +2,7 @@
 #include <vector>
 #include <algorithm>
 #include <string>
+#include <functional>
 #include <memory>
 
 // Change function `areaLessThan20` into lambda.
@@ -31,9 +32,7 @@ class Circle {
 using CirclePtr = shared_ptr<Circle>;
 using Collection = vector<CirclePtr>;
 
-bool areaLessThan20(CirclePtr s) {
-    return (s && s->getArea() < 20);
-}
+
 
 void printCollection(const Collection& collection) {
     for (const auto & it : collection) {
@@ -53,7 +52,8 @@ void printAreas(const Collection& collection) {
 
 void findFirstShapeMatchingPredicate(const Collection& collection,
                                      std::string info,
-                                     bool (*predicate)(CirclePtr s)) {
+                                     std::function<bool(CirclePtr)>predicate){
+                                    //  bool (*predicate)(CirclePtr s)) {{}
     auto it = std::find_if(collection.begin(), collection.end(), predicate);
     if(it != collection.end()) {
         cout << "First shape matching predicate: " << info << endl;
@@ -84,9 +84,15 @@ int main() {
     cout << "Areas after sort: " << std::endl;
     printAreas(circles);
 
+
+auto  areaLessThanX = [x=20](CirclePtr s)->bool{
+return (s && s->getArea() < x);
+};
+
+
     findFirstShapeMatchingPredicate(circles,
                                     "area less than 20",
-                                    areaLessThan20);
+                                    areaLessThanX);
 
     return 0;
 }

exercises/dangling.cpp

@@ -2,7 +2,7 @@
 
 auto getIndexGenerator() {
     int value = 0;
-    auto lambda = [&value] {
+    auto lambda = [value] () mutable {
         return value++;
     };
     return lambda;
@@ -20,8 +20,9 @@ int getFive() {
 int main() {
     auto generator = getIndexGenerator();
     [[maybe_unused]] int value = getFive();
+
     for (int i = 0; i < 10; ++i) {
-        std::cout << generator();
+       generator();
     }
     std::cout << '\n';
     return 0;

exercises/main.cpp

@@ -0,0 +1,15 @@
+
+#include <iostream>
+#include <functional>
+
+  constexpr auto add = [](int n, int m) {
+    auto L = [=] { return n; };
+    auto R = [=] { return m; };
+    return [=] { return L() + R(); };
+};
+
+
+int main() {
+
+static_assert(add(3, 4)() == 7);
+}