#include
#include
using namespace std;

class Distance
{
??? private:
??????? double feet;???????????? // 0 to infinite
??????? double inches;
??? public:
??????? static const double absError=0.0000001;
??????? static? bool IsEqual(double a, double b)
??????? {
??????????? if (a==b)
??????????????? return true;
??????????? if (fabs(a-b) ??????????????? return true;
??????????? return false;
??????? }
??????? // required constructors
??????? Distance()
??????? {
???????????? feet = 0;
???????????? inches = 0;
??????? }
??????? Distance(double f, double i)
??????? {
???????????? feet = f;
???????????? inches = i;
??????? }
??????? /**重新设置数据**/
??????? void set(double f, double i)
??????? {
???????????? feet = f;
???????????? inches = i;
??????? }
??????? /**重载赋值运算符后 交换两个类的数据**/
??????? void swap(Distance& d)
??????? {
??????????? Distance temp;
??????????? temp=*this;
??????????? *this=d;
??????????? d=temp;
??????? }
??????? // method to display distance
??????? void displayDistance()
??????? {
??????????? cout <<" Feet: " << feet << " Inches:" << inches < ??????? }
??????? /*** overloaded minus (-) operator? ***/
??????? Distance operator- ()
??????? {
???????????? feet = -feet;
???????????? inches = -inches;
???????????? return Distance(feet, inches);
??????? }
??????? /*** overloaded < operator 重载小于号 ***/
??????? bool operator <(const Distance& d)
??????? {
???????????? if((feet - d.feet ???????????? {
??????????????? return true;
???????????? }
???????????? return false;
??????? }
??????? /*** overloaded > operator? 重载大于号***/
??????? bool operator > (const Distance& d)
??????? {
???????????? if((feet -d.feet>absError)||(feet == d.feet && inches - d.inches>absError))
???????????? {
??????????????? return true;
???????????? }
???????????? return false;
??????? }
??????? /*** overloaded == operator 重载等于号 ***/
??????? bool operator ==(const Distance& d)
??????? {
???????????? if(IsEqual(feet,d.feet) && IsEqual(inches,d.inches))
???????????? {
??????????????? return true;
???????????? }
???????????? return false;
??????? }

};

int main()
{
??? Distance D1(20.08,5.12 ), D2(20.13, 4.20);
??? cout<<"before swap :\n";
??? cout<<"D1:---->? ";
??? D1.displayDistance();
??? cout<<"D2:---->? ";
??? D2.displayDistance();
??? if( D1 < D2 )
??? {
????? cout << "D1 is less than D2 " << endl;
??? }
??? else
??? {
????? cout << "D2 is less than D1 " << endl;
??? }
??? D1.swap(D2);
??? cout<<"after swap :\n";
??? cout<<"D1:---->? ";
??? D1.displayDistance();
??? cout<<"D2:---->? ";
??? D2.displayDistance();

???? if( D1 < D2 )
??? {
????? cout << "D1 is less than D2 " << endl;
??? }
??? else
??? {
????? cout << "D2 is less than D1 " << endl;
??? }

??? double a=0.33,b=0.33;
??? cout<<"\ndouble a=0.33,b=0.33 then Distance::IsEquall(a,b) = "
??????? <

??? cout<<"after? set(199.1,11.05)\n";
??? D1.set(199.1,11.05);
??? D2.set(199.1,11.05);
??? D1.displayDistance();
??? D2.displayDistance();