Re: Quick question on returning references to local variables
On 22 Jul., 05:44, ankur <ankur.a.agar...@gmail.com> wrote:
My question is , in the code below , how is it that the last ob1.show
() displays 15 50, even though the temp object in overloaded operator
function has been destroyed as illustrated by the destructor call.
If the temp object has been destroyed then how come ob1 gets the
updated values:
#include <iostream>
using namespace std;
class loc {
int longitude, latitude;
public:
loc() {
cout <<"In argument less constructor"<< endl;
longitude = 0;
latitude = 0;
}
loc(int lg, int lt) {
longitude = lg;
latitude = lt;
cout << "In the constructor with arguments "
<< longitude <<" " << latitude << endl;
}
~loc () {
cout << " In Destructor " << longitude << " "
<< latitude << endl;
}
void show() {
cout << longitude << " ";
cout << latitude << "\n";
}
loc& operator+(loc op2);};
// Overload + for loc.
loc& loc::operator+(loc op2)
{
cout << "In operator before temp" << endl;
loc temp;
cout << "In operator after temp" << endl;
temp.longitude = op2.longitude + longitude;
temp.latitude = op2.latitude + latitude;
return temp;
}
Don't ever return references to local automatic objects. Honor your
compiler's warnings. You cannot rely on any behaviour in this case.
You're "lucky" that your program didn't crash.
Cheers!
SG
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