@@ -1,3 +1,3 @@
-cmake_minimum_required(VERSION 3.0)
+cmake_minimum_required(VERSION _3.0)
 file(GLOB SOURCES RELATIVE ${CMAKE_SOURCE_DIR} "*.c")
 add_executable(main ${SOURCES})
@@ -24,9 +24,9 @@
         1.  [Value category cheatsheet](https://github.com/jeaye/value-category-cheatsheet/tree/14aef17fb5ab9c35416ec62ac0d45eb12729901f/resources/code)
     1.  [Function](function.cpp)
         1.  [Operator overload](operator_overload.cpp)
+            1.  [Cast operator](cast_operator.cpp)
         1.  [Default parameters](default_parameters.cpp)
         1.  [Parameter without name](parameter_without_name.cpp)
-        1.  [Conversion function](conversion_function.cpp)
         1.  [Lambda](lambda.cpp)
         1.  [Trailing return type](trailing_return_type.cpp)
     1.  [explicit](explicit.cpp)
 
@@ -0,0 +1,42 @@
+/*
+Allows to convert objects to primitives and other objects.
+
+http://en.cppreference.com/w/cpp/language/cast_operator
+*/
+
+#include "common.hpp"
+
+class ToInt {
+    public:
+        int i;
+        ToInt(int i) : i(i) {}
+        operator int() {
+            return this->i;
+        }
+};
+
+class ToToInt {
+    public:
+        int i;
+        ToToInt(int i) : i(i) {}
+        operator ToInt() {
+            return ToInt(this->i);
+        }
+};
+
+int main() {
+    // Explicit cast.
+    assert((int)ToInt(0) == 0);
+
+    // Implicit conversion.
+    assert(ToInt(0) == 0);
+
+    // ERROR: Only a single implicit cast is possible at a time.
+    //assert(ToToInt(0) == 0);
+
+    // OK, on implicit cast.
+    assert((ToInt)ToToInt(0) == 0);
+
+    // OK, all explicit.
+    assert((int)(ToInt)ToToInt(0) == 0);
+}
@@ -74,6 +74,13 @@ int main() {
     manual_ptr_test();
     assert(Base::count == 10);
 
+    // Convert to raw pointer.
+    // Not possible.
+    {
+        std::unique_ptr<int> p(new int);
+        //int *raw = p;
+    }
+
     // Copy constructor is deleted.
     // This is what imposes uniqueness.
     {