Hi folks,
I am learning operator overloading concept in c++, wrote sample program to test overloading of unary operator '!' and '-'.
Code will work if i use them as friend function but not for member function. Can anybody tell where am i going wrong in function bool operator!(const co_ordi &a) and co_ordi operator-(const co_ordi &x); . Is that correct way to declare and define.
I am getting following error
Error:
op_ovld_unary.cc:18: error: ‘bool co_ordi::operator!(const co_ordi&)’ must take ‘void’
op_ovld_unary.cc: In function ‘int main()’:
op_ovld_unary.cc:45: error: no match for ‘operator!’ in ‘!a’
op_ovld_unary.cc:45: note: candidates are: operator!(bool) <built-in>
op_ovld_unary.cc:50: error: no match for ‘operator-’ in ‘-b’
op_ovld_unary.cc:22: note: candidates are: co_ordi co_ordi::operator-(const co_ordi&)
#include<iostream>
using namespace std;
class co_ordi
{
int cx,cy,cz;
public:
co_ordi(int x=0,int y=0,int z=0):cx(x),cy(y),cz(z)
{
cout<<"in c_tor="<<cx<<cy<<cz<<endl;
}
void get_coordi()
{
cout<<"x="<<cx<<"y="<<cy<<"z="<<cz<<endl;
}
// friend co_ordi operator- (const co_ordi &a);
// friend bool operator! (const co_ordi &a);
bool operator!(const co_ordi &a)
{
return (a.cx == 0 && a.cy == 0 && cz==0);
}
co_ordi operator-(const co_ordi &x)
{
co_ordi k(-x.cx,-x.cy,-x.cz);
return k;
}
};
/**co_ordi operator- (const co_ordi &x)
{
cout<<"me minus"<<endl;
return co_ordi(-x.cx,-x.cy,-x.cz);
}
bool operator! (const co_ordi &a)
{
return (a.cx == 0 && a.cy == 0 && a.cz == 0);
}**/
int main()
{
co_ordi a,b(4,5,6);
if(!a)
cout<<"a at origin"<<endl;
else
cout<<"a not at origin"<<endl;
b.get_coordi();
b = -b;
b.get_coordi();
return 0;
}