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

void loop() {

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

  // process newline characters from pressing enter key
  while (Serial.available() > 0) {
      char c = Serial.read();
      if (c == '\n' || c == '\r') {
          break; // Exit the loop when newline or carriage return is found
      }
  }
}

// User-defined function to calculate the area of a circle
float calculateCircleArea(float r) {
  float area = PI * r * r;
  return area;
}