C++类构造函数

#include <iostream>

using namespace std;

class Line {
   public:
      void setLength( double len );
      double getLength( void );
      Line();     // This is the constructor
   private:
      double length;
};

// Member functions definitions including constructor
Line::Line(void) {
   cout << "Object is being created" << endl;
}
void Line::setLength( double len ) {
   length = len;
}
double Line::getLength( void ) {
   return length;
}

// Main function for the program
int main() {
   Line line;

   // set line length
   line.setLength(6.0); 
   cout << "Length of line : " << line.getLength() <<endl;

   return 0;
}