Table of Contents

How much wood?

Problem

  • We want to build some 2D structures out of wood. How much wood will we need?
  • User can choose (each option prompts for dimensions):
    • A house
      • Height of wall
      • Height and width of roof
    • An ice cream cone
      • Height and width of cone
      • Height of ice cream
    • A train car
      • Height of car
      • Height of wheel
  • Report back the total area of wood needed

Solution

/*
Test case 1:
Input: 3, 1, 2 (train example)
Expected Ouput: 8.283
Actual: 
 
Test case 2:
Input: 2, 1, 2, 1 (ice cream cone)
Expected Output: 2.5708
Actual Output: 2.5708
 
Test case 3:
Input: 1, 1, 1, 2 (house)
Expected: 2
Actual: 
*/
 
#include <iostream>
#include <string>
 
using namespace std;
 
const double PI = 3.14159265359;
const double MAX_DIMENSION = 100000;
 
// These must be declared before the function that calls them (e.g., main), but can be defined below
void print_menu();
double get_user_input(double min, double max);
 
double calculate_circle_area(double radius);
double calculate_square_area(double side_length);
double calculate_triangle_area(double width, double height);
 
double calculate_house_area(double wall_height, double roof_height, double roof_width);
double calculate_ice_cream_area(double cone_height, double cone_width, double ice_cream_height);
double calculate_train_area(double car_height, double wheel_height);
 
int main()
{
	double area = 0.0;
 
	// prompt user for choice
	print_menu();
 
	int choice = get_user_input(1, 3);
 
	// if choice is 1
	if (choice == 1)
	{
		// prompt for house and roof dimensions
		double wall_height, roof_height, roof_width;
		cout << "You chose house. How tall's the wall? ";
		wall_height = get_user_input(0,MAX_DIMENSION);
 
		cout << "How tall's the roof? ";
		roof_height = get_user_input(0, MAX_DIMENSION);
 
		cout << "How wide's the roof? ";
		roof_width = get_user_input(0, MAX_DIMENSION);
 
		area += calculate_house_area(wall_height, roof_height, roof_width);
	}
 
	// if choice is 2
	else if (choice == 2)
	{
		// prompt for ice cream cone dimensions
		double cone_height, cone_width, ice_cream_height;
		cout << "You chose ice cream cone. How tall's the cone? ";
		cone_height = get_user_input(0, MAX_DIMENSION);
 
		cout << "How wide's the cone? ";
		cone_width = get_user_input(0, MAX_DIMENSION);
 
		cout << "How tall's the ice cream? ";
		ice_cream_height = get_user_input(0, MAX_DIMENSION);
 
		area += calculate_ice_cream_area(cone_height,cone_width, ice_cream_height);
	}
 
	// if choice is 3
	else if (choice == 3)
	{
		// prompt for train dimensions
		double car_height, wheel_height;
		cout << "You chose the train. How tall's the car? ";
		car_height = get_user_input(0, MAX_DIMENSION);
 
		cout << "How tall's the wheel? ";
		wheel_height = get_user_input(0, MAX_DIMENSION);
 
		area += calculate_train_area(car_height, wheel_height);
	}
 
	// Report total area
	cout << "Total area of wood needed is " << area << " square inches" << endl;
 
	system("pause");
	return 0;
 
}
 
/*
Just print the menu (doesn't read input)
*/
void print_menu()
{
	cout << "Choose from the following\n"
		<< "1. A 2d House\n"
		<< "2. A 2d ice cream cone\n"
		<< "3. A 2d train car\n"
		<< "Choice: ";
 
	return;
}
 
/*
Reads for integer input and reprompts until valid floating-point input is provided within range
@param min minimum value for range of input
@param max maximum value for range of input
@return first valid input floating-point number
*/
double get_user_input(double min, double max)
{
	int input;
	// read in from cin
	cin >> input;
 
	// while it's bad (non-int or not in range)
	while (cin.fail() || input < min || input > max)
	{
		// send message, reprompt
		cout << "That's bad input. Gimme a value between " << min << " and " << max << ":";
		if (cin.fail())
		{
			cin.clear();
			string dummy;
			cin >> dummy;
		}
		// read again from cin
		cin >> input;
	}
 
	return input;
}
 
/*
	Calculate the area of a circle given the radius
	@param radius the radius of the circle
	@return the area of the circle given the radius
*/
double calculate_circle_area(double radius)
{
	double area = 0.0;
 
	area = PI * pow(radius, 2);
 
	return area;
}
 
/*
	Calculate the area of a square given the side length
	@param side_length the length of the side of the square
	@return the area of the square
*/
double calculate_square_area(double side_length)
{
	double area = 0.0;
 
	area = pow(side_length, 2);
 
	return area;
}
 
/*
	Calculate the area of a triangle given the width and height
	@param width length of the unequal edge of an isoseles triangle
	@param height length of the line perpendicular to the unequal edge 
		of the isosoles triangle extending to the opposite corner
	@return the area of the triangle
*/
double calculate_triangle_area(double width, double height)
{
	double area = 0.0;
 
	area = width * height / 2;
 
	return area;
}
 
/*
	Calculate the area of a house given the dimensions
	@param wall_height the height of a wall (the house is square)
	@param roof_height the height of the roof (see height of triangle in calculate_triangle_area function)
	@param roof_width the width of the roof (see width of triangle in calculate_triangle_area function)
	@return the area of the house as 2d object
*/
double calculate_house_area(double wall_height, double roof_height, double roof_width)
{
	double area = 0.0;
 
	area += calculate_square_area(wall_height);
	area += calculate_triangle_area(roof_width, roof_height);
 
	return area;
}
 
/*
	Calculate the area of an ice cream cone given dimensions
	@param cone_height the height of the ice cream above the cone (i.e., radius of a half circle)
	@param cone_width the width of the cone (see width of triangle in calculate_triangle_area function)
	@param ice_cream_height the height of the cone (see width of triangle in calculate_triangle_area function)
	@return the area of the ice cream as 2d object
*/
double calculate_ice_cream_area(double cone_height, double cone_width, double ice_cream_height)
{
	double area = 0.0;
 
	area += calculate_triangle_area(cone_width, cone_height);
	area += calculate_circle_area(ice_cream_height) / 2.0;
 
	return area;
}
 
/*
	Calculate the area of a train given dimensions
	@param car_height the height of the train car (which is also 2x the length)
	@param wheel_height the diameter of the train car wheel
	@return the area of the train as 2d object
*/
double calculate_train_area(double car_height, double wheel_height)
{
	double area = 0.0;
 
	area += 2 * calculate_square_area(car_height);
	area += 2 * calculate_circle_area(wheel_height / 2.0);
 
	return area;
}
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cs-142/how-much-wood.txt · Last modified: 2015/05/19 18:35 by cs142ta
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