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It would be ideal to find a way of calling a certain function that only offers the most useful parameters (like setting the speed) and which handles technical details (switching pins on and off) internally. | It would be ideal to find a way of calling a certain function that only offers the most useful parameters (like setting the speed) and which handles technical details (switching pins on and off) internally. | ||
==Possible solution: Data and code in one package „Classes“ and „Objects“== | |||
C++ (and also Arduino) provides a specific feature that can solve our problem: Classes and Objects | |||
A Class predefines common qualities of a group of Objects. | |||
It for instance determines that every motor has the possibility to exert a certain amount of throttle. | |||
The corresponding program could look like this: | |||
''class Motor{ | |||
public: // the following qualities and methods are visible from the outside. | |||
void setThrottle(int newThrottle); // every motor has the possibility to exert trottle. | |||
}'' | |||
Now the computer knows that there is a class called „Motor“. | |||
This class (class) provides a function called „setThrottle“ that is called as an argument by using a number (int) and that does not return anything (void). | |||
==Classes are Data-types== | |||
We can use our „Motor“ - class the same way we are using other data - types (int, long, float). | |||
The following lines use that quality in order to implement two motors: | |||
''Motor leftMotor; // declare an object of the type „Motor“ called „leftMotor“ | |||
Motor rightMotor; // declare another object of the type „Motor“ called „rightMotor“ | |||
'' | |||
==Calling inner functions of a class (Methods)== | |||
Imagine we want to drive the left motor with full throttle whereas the right motor should stop completely. | |||
This can be expressed as follows: | |||
''// the objetcs name „leftMotor“ and the herein implemented function „setThrottle“ are separated by a dot. | |||
leftMotor.setThrottle(255); | |||
rightMotor.setThrottle(0); | |||
'' | |||
A positive side effect: your program gains readability by picking distinct names for your Objects and Methods. | |||