void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  while(!Serial){continue;}
  Serial.println("Enter radius of circle:");
}

void loop() {
  
  if (Serial.available() > 0) {
    float radius = Serial.parseFloat();
    float area = calculateCircleArea(radius);
    Serial.print("The area of circle with radius ");
    Serial.print(radius);
    Serial.print(" is: ");
    Serial.println(area, 2);  //print area with two decimal places
    Serial.println("Enter another radius:");
  }


}

//user defined function to calculate the area of a circle

float calculateCircleArea(float r) {
  float area = PI * r * r;
  return area;
}