#include <stdio.h>
#include <math.h>

double areaOfCircle(double radius) {
  double circle_area;
  circle_area = 3.14159 * pow(radius, 2);
  return circle_area;
}

double areaOfRectangle(double length, double width) {
  double rectangle_area;
  rectangle_area = length * width;
  return rectangle_area;
}

double areaOfTriangle(double base, double height) {
  double triangle_area;
  triangle_area = 0.5 * base * height;
  return triangle_area;
}

int main(void) {
  int selection;

  do {
    // menu
    printf("Geometry Calculator\n\n1. Calculate the Area of a Circle\n2. Calculate the Area of a Rectangle\n3. Calculate the Area of a Triangle\n4. Quit\nEnter your choice: ");
    scanf("%d", &selection);
    switch(selection) {
      case 1:
        double radius;
        printf("Enter circle radius: ");
        scanf("%lf", &radius);
        printf("The area of the circle is %f.\n", areaOfCircle(radius));
      case 2:
        double length, width;
        printf("Enter rectangle length: ");
        scanf("%lf", &length);
        printf("Enter rectangle width: ");
        scanf("%lf", &width);
        printf("The area of the rectangle is %f", areaOfRectangle(length, width));
      case 3:
        double base, height;
        printf("Enter triangle base length: ");
        scanf("%lf", &base);
        printf("Enter triangle height: ");
        scanf("%lf", &height);
        printf("The area of the triangle is %f", areaOfTriangle(base, height));
      case 4:
        break;
    }
  } while (selection != 4);
  return 0;
}