#include "stdstuff.h"


double square (double x) {

    return x * x;

}


double hypotenuse (double s1, double s2) {

    return sqrt (square(s1) + square(s2));

}


double roofArea (double length, double width, double height) {

     double l_side_area, w_side_area;

     // work out area of triangle having base of length 'length'
     l_side_area = (length * hypotenuse(height, width / 2)) / 2;

     // work out area of triangle having base of length 'width'
     w_side_area = (width * hypotenuse(height, length / 2)) / 2;

     // return total area of the roof
     return (2 * l_side_area) + (2 * w_side_area);

}

int main () {

     double length, width, height;

     // prompt user for and read the input quantities
     cout << "Please enter length, width and height of roof: ";
     cin >> length >> width >> height;

     // output the result
     cout << "The total area of the roof is "
          << roofArea (length, width, height) << endl;

     pause();
     return 0;
}