how to run a class in c++ code example

Example 1: c++ class method example

class Object {
public:
	int var;
	void setVar(int n) {
		var = n;
	}
	int getNum() {
		return var;
	}
};

int main() {
	Object obj;
	obj.setVar(13);
	std::cout << obj.getNum() << std::endl;
	return 0;
}

Example 2: new class * [] c++

/*
 Keyword "this"
You can use keyword "this" to refer to this instance inside a class definition.

One of the main usage of keyword this is to resolve ambiguity between the names of 
data member and function parameter. For example:
*/
class Circle {
private:
   double radius;                 // Member variable called "radius"
   ......
public:
   void setRadius(double radius) { // Function's argument also called "radius"
      this->radius = radius;
         // "this.radius" refers to this instance's member variable
         // "radius" resolved to the function's argument.
   }
   ......
}