some changes ; mostly new examples

OOP/methodes/car_speed.cpp

@@ -0,0 +1,22 @@
+#include <iostream>
+
+/*
+    This here that we have is just another demo of the OOP in c++ ; we have the function that we have in the last example and then we usefully do something
+    with this function ;
+*/
+
+using namespace std;
+
+class Car {
+    public:
+        int speed(int max_speed);
+};
+
+int Car::speed(int max_speed) {
+    return max_speed;
+}
+
+int main() {
+    Car volvo;
+    volvo.speed(600);
+}