classes

cpp/classes/README.md

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+# Classes in C++
+
+In c++ classes are defined using a header file and the implementation in a
+regular .cpp file. Explanations to the structure can be found in the files themselves
+
+## Relevant files
+
+- [car.h](./car.h)
+- [car.cpp](./car.cpp)

cpp/classes/car.cpp

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+// include the header file
+#include "car.h"
+
+// include necessary libraries and namespaces
+#include <iostream>
+#include <string>
+using namespace std;
+
+// define the implementation for car.print_info()
+void car::print_info()
+{
+  cout << "Car Information:" << endl;
+  // fields that are defined in the header file can just be used like normal variables here
+  cout << "- manufacturer: " << manufacturer << endl;
+  cout << "- model: " << model << endl;
+}
+
+/*
+
+That's everything for the .cpp file. 
+Since fields don't have an implementation and are already defined in the header file, they can be left out here.
+
+*/

cpp/classes/car.h

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+// #pragma once is usually included in header files to make sure they are only loaded once
+// it's a simpler version of include guards, which are necessary to prevent conflicts
+#pragma once
+/*
+
+in case #pragma once is not supported by your compiler you'll need more basic include guards
+in this case it would be
+#ifndef car_h
+#define car_h
+
+...class contents
+
+#endif
+
+*/
+
+// including a necessary library and namespace to work with strings
+#include <string>
+using namespace std;
+
+// define the class
+class car
+{
+  // define the visibility of the following fields and methods
+  // in this case everything is public since visibility is a topic in future lessons
+  public:
+    // define two strings, manufacturer and model
+    std::string manufacturer;
+    std::string model;
+
+    // define a function that will print out information
+    void print_info();
+};
+
+/*
+
+That completes the header file, as you can see, there are no implementations in here.
+That's because they will be added in the car.cpp file.
+
+*/

cpp/classes/main.cpp

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+#include "car.h"
+#include <cstring>
+
+int main() {
+  // create a new car and store it in the variable 'a'
+  // in contrast to java, c++ does not need initialization with the 'new' keyword here.
+  car a;
+  // set some data for that car
+  a.manufacturer = "Benz";
+  a.model = "Velo";
+
+  // do the same for a second car
+  car b;
+  b.manufacturer = "Ford";
+  b.model = "Model T";
+
+  // use a function of the car class to print out the information
+  a.print_info();
+  b.print_info();
+}