C++公共成员

#include <iostream>

using namespace std;

class Line {
   public:
      double length;
      void setLength( double len );
      double getLength( void );
};

// Member functions definitions
double Line::getLength(void) {
   return length ;
}

void Line::setLength( double len) {
   length = len;
}

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

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

   // set line length without member function
   line.length = 10.0; // OK: because length is public
   cout << Length of line :  << line.length <<endl;

   return 0;
}