#import <Foundation/Foundation.h>
 
// function declaration statements (i.e. function prototypes)
double circleArea(double radius);
double rectangleArea(double width, double height);
 
int main (int argc, const char * argv[])
{
   NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

   double pictureWidth = 0.0;       // width of picture
   double pictureHeight = 0.0;      // height of picture
   double pictureSurfaceArea = 0.0; // surface area of picture
   double circleRadius = 0.0;       // radius of circle
   double circleSurfaceArea = 0.0;  // surface area of circle

   pictureWidth = 8;
   pictureHeight = 4.5;
   circleRadius = 5.0;

   pictureSurfaceArea = pictureWidth * pictureHeight;
   circleSurfaceArea = circleArea(circleRadius); 

   NSLog(@"Area of picture: %f. Area of circle: %10.2f.", pictureSurfaceArea, circleSurfaceArea);

   [pool drain];
   return 0;
}// end of main
 
// returns the area of a circle with radius radius
double circleArea(double radius)
{
   double area = 0.0;
   area = 3.1416 * radius * radius;
   return area;
}// end of circleArea
 
// returns area of a rectangle with width of width and height of height
double rectangleArea(double width, double height)
{
   return width * height;
}// end of rectangleArea