Lab2 - Calculate circumference and area of a circle from its diameter (function)

void setup(){
 float r1 = cal_area(7);
 float r2 = cal_circumference(7);
}

 float cal_area(float diameter){
  
 //Calculate area of a circle from its diameter
   float area_of_a_circle;
  
 //equation
 area_of_a_circle = PI*(diameter/2)*(diameter/2);

 //result
 println("Diameter is" ,diameter);
 println("Area of a circle is" ,area_of_a_circle);
 return area_of_a_circle;
}

float cal_circumference(float diameter){
 //Calculate circumference from its diameter
  float circumference;
 
 //equation
 circumference = PI*diameter;
 //result
 println("Circumference is" ,circumference);
 return circumference;
}