question about some variables in my code

Hello guys!

I want to program something that tells me how many gallons of paint I need and what the total cost of the painting . I gotta say I am new to this, I hope the question dosen't seem that silly

Code:

// Headers and Other Technical Items

#include <iostream>  
using namespace std;

// Function Prototypes

void pause(void);

// 

double       length;
double       width;
double       height;
double       price_gal_paint;
int          coverage_gal_paint;
double       total_area;
int          total_gal_paint;
double       total_cost;
//******************************************************
// main
//******************************************************

int main(void)
  {
  // Input	
  cout << "\nEnter the price of 1 gallon of paint";
  cin >> price_gal_paint;
  cout << "\nEnter the length of the house ";
  cin >> length;
  cout << "\nEnter the width of the house ";
  cin >> width;
  cout << "\nEnter the height of the house ";
  cin >> height;
  cout << "\nEnter the amount of square foot one gallon will cover ";
  cin >> coverage_gal_paint;
  // Process
  
  // calculate the total area of the building by
  x = length * height * 2 ;
  y = width * height * 2;
  total_area = x + y;
  
  //calculate the number of gallons of paint needed by
  
  total_gal_paint = total_area / coverage_gal_paint;
  total_gal_paint = total_area / coverage_gal_paint + 0.9999;
  
  total_cost = total_gal_paint * price_gal_pain;
  // Output
  cout << "\nThe number of gallons of paint is -------->: ";
  cout << answer;
  cout << "\nThe total cost of the paint is -------->: ";
  cout << answer;
  pause();
  return 0;
  }

//******************************************************
// pause
//******************************************************

void pause(void)
  {
  cout << "\n\n";
  system("PAUSE");
  cout << "\n\n";
  return;
  }

I hope everything is right. But I do have a question about the following code..

Code:

 // calculate the total area of the building by
  x = length * height * 2 ;
  y = width * height * 2;
  total_area = x + y;

I know it cant be just x and y now. But if I did total_area for x and y it wouldn't calculate it right. I think I have enough variables.. I don't know.. I kinda don't know how do do this part.
I believe I need to more variables for this..?

Thank you!!

Since the formula for area of a really-open box (no floor or ceiling) is 2lh+2wh, you could just assign that to total_area, without doing it in stages like you're currently doing.

Well, but I would like to do it this way. Makes it kinda esier for me. Can I still assign total_area to it?

If you mean assign "it" to total_area, then I suppose, depending on what "it" is.

Sorry, I mean it like this:

PHP Code:


// calculate the total area of the building by
  total_area = length * height * 2 ;
  total_area = width * height * 2;
  total_area = x + y; 


As I already said, this looks wrong to me. Maybe it is not..not sure. But then You have 3 values assigned to total_area instead of just the result.

Edit:

No, that dosen't work. I forgot about the total_area = x + y. Of course, it couldn't be x and y. Seems so easy..but I just do't get it.

I got it working now. But I still would like to know how do to it the way I wanted to do it. I took 2lh+2wh