السلام عليكم
ممكن تشرحون لي هذا البرنامج لاني حاولت ان افهمه ولكن لم استطع
وخصوصا لماذا وضعنا const
class Distance //English Distance class
{
private:
int feet;
float inches;
public: //constructor (no args)
Distance() : feet(0), inches(0.0)
{ } //constructor (two args)
Distance(int ft, float in) : feet(ft), inches(in)
{ }
void getdist() //get length from user
{
cout << “\nEnter feet: “; cin >> feet;
cout << “Enter inches: “; cin >> inches;
}
void showdist() const //display distance
{ cout << feet << “\’-” << inches << ‘\”’; }
Distance operator + ( Distance ) const; //add 2 distances
};
//--------------------------------------------------------------
//add this distance to d2
Distance Distance::operator + (Distance d2) const //return sum
{
int f = feet + d2.feet; //add the feet
float i = inches + d2.inches; //add the inches
if(i >= 12.0) //if total exceeds 12.0,
{ //then decrease inches
i -= 12.0; //by 12.0 and
f++; //increase feet by 1
} //return a temporary Distance
return Distance(f,i); //initialized to sum
}
////////////////////////////////////////////////////////////////
int main()
{
Distance dist1, dist3, dist4; //define distances
dist1.getdist(); //get dist1 from user
Distance dist2(11, 6.25); //define, initialize dist2
dist3 = dist1 + dist2; //single ‘+’ operator
dist4 = dist1 + dist2 + dist3; //multiple ‘+’ operators
//display all lengths
cout << “dist1 = “; dist1.showdist(); cout << endl;
cout << “dist2 = “; dist2.showdist(); cout << endl;
cout << “dist3 = “; dist3.showdist(); cout << endl;
cout << “dist4 = “; dist4.showdist(); cout << endl;
return 0;
}
