C++ coding style

Next to consistency as a main aspect of good code, the second most important aspect is a certain style which the average c++ programmer is capable to read and understand properly. Therefore the following documents states the essential naming conventions.

Naming conventions

Variables

The name of a variable should be as accurate as possible and as short as possible at the same time.

Example:

// don't
int x; 
x = 10 + 5;
// do
int sum
sum = 10 + 5;

Global/Local variables Global/Local variables should be defined in a snake_case style.

Example:

int global_variable; 

Private variables Private variables should be defined the same way as global variables. The main difference for private variables is a defined prefix _.

Example:

int _private_variable; 

Constants & Preprocessor Values

Constants are expression with a fixed value. They are defined with the key `const. The naming convention for constants and preprocessor values prescribes that all letters are upper case letters with snake case subdivision

Example:

const int PI_VALUE = 3.14159; 

Functions

A function is a block of code which runs when it's called. Data in form of parameters can be passed into a function. Functions can be written as non-returning and returning type. Functions should start with a lower case letter. The following word should be upper case. This method is called camelCase

Example:

void exampleFunktion()
{
   // do some stuff
}

Classes (Types, Template parameters)

C++ is a object-oriented programming language. Therefore it's all about creating objects which contain both data and functions for a certain task.

In the example picture shown above, there is the class car defined, which has certain methods and attributes. This class can be used to create different objects which share the same set of properties with different values.

A class should be defined with all upper case (PascalCase) notation.

Example:

class Car 
{
  public:
    string brand; 
    int max_speed; 
    int power;
    Car(string ini_brand, int ini_speed, ini_power)
    {
       brand = ini_brand; 
       max_speed = ini_speed; 
       power = ini_power; 
    }

  private: 
    int _current_speed; 
};

void GeneralCar::setSpeed(int new_speed)
{
    _current_speed = new_speed; 
}

int main()
{
   // declaration of two objects
   Car car1("Auto1", 200, 100); 
   Car car2("Auto2", 300, 200); 

   //setting the speed
   car1.setSpeed(250);

   return 0;   
}

Braces

In order to get a clear structure the following braces scheme should be taking into account when programming. Every left brace ({) should be appear by itself on the line below it the block it opens. The corresponding right brace (}) should be placed by itself in the same position th appropriate number of lines later in the file.

Example

if(car.speed == "fast")
{
   car.price = "high"; 
}
else
{
   car.price = "low"; 
}

The indentation should always be made with a tab. For every hierarchy step one tab has to be added.

Example

if(car.speed == "fast")
{
   car.price = "high";
   if(car.weight >= 1000)
   {
      car.type = "Truck"; 
   }
}
else
{
   car.price = "low"; 
}

Comments

If the section of code is not clearly understandable there should be a short description of the current function in form of a comment. For commenting block // should be used.

Example DON'T

// divides up two double values
double division(double dividend, double divisor)
{
   // this is the result variable
   double div; 
   // the result is calculated here:
   div = dividend / divisor; 
   // here the result is given back
   return div;
}