Distance and Area

[ccaddiso]

I want to retrieve my x1, x2, y1, and y2 from a text file using getline, but i don't know how.

const double PI = 2.0 * asin(1.0);
 
// class declaration
class Point
{
  protected:
    float x;
    float y;
  public:
    Point(float = 0.0, float = 0.0);  //constructor
    float distance(Point&);
    float area();
};
 
// implementation section
Point::Point(float xval, float yval)
{
  x = xval;
  y = yval;
}
 
float Point::distance(Point& b)
{
  return (sqrt(pow((x-b.x),2) + pow((y-b.y),2)));
}
 
float Point::area()
{
  return 0;
}
 
// class declaration for the derived Circle class
class Circle : public Point
{
  protected:
    double radius; // add an additional data member
  public:
    Circle(float = 0.0, float = 0.0, float = 1.0);  // constructor
    float distance(Circle&);
    float area();
};
 
// implementation section for Circle
Circle::Circle(float centerx, float centery, float r)  // constructor
{
  x = centerx;
  y = centery;
  radius = r;
}
 
float Circle::distance(Circle& b)
{
   return (Point::distance(b)); // note the base function call
}
 
float Circle::area()   // this calculates an area
{
  return (PI * pow(radius,2));
};
 
int main()
string line;
ifstream file("a8,txt");
if (file.is_open())
{
while(!file.eof())
{
getline(file,line);
 
cout <<"the points are" << line;

[Ganon11]

If you have an ifstream, you can say:

file >> val1 >> val2;

instead of using getline. This is much easier.

If you insist on using getline, you will have to input to a string variable (recommended: std::string), and then break that string up into separate parts to get the different numbers.