Compiling errors Overloading operator>> in c++

[supernick]

I just started learning c++ and i'm currently stuck on the chapter on overloading functions. I'm having compiling errors when I compile this program, i'm using ubuntu os with g++ compiler. I removed the use of some variables to reduce the error messages.



error:
overloading.cc: In function ‘std::istream& operator>>(std::istream&, const PhoneNumber&)’:
overloading.cc:32: error: no match for ‘operator>>’ in ‘std::operator>> [with _CharT = char, _Traits = std::char_traits<char>](((std::basic_istream<char, std::char_traits<char> >&)((std::istream*)input)), std::setw(4)) >> num->PhoneNumber::areaCode’ ............etc




#include <iostream>

using std::cout;
using std::cin;
using std::endl;
using std::ostream;
using std::istream;

#include <iomanip>

using std::setw;


class PhoneNumber{
public:
friend ostream &operator<<(ostream&, const PhoneNumber &);
friend istream &operator>>(istream&, const PhoneNumber &);

private:
char areaCode[ 4];
char exchange[ 4];
char line[ 5];
};

ostream &operator<<(ostream &output, const PhoneNumber &num){
output << "(" << num.areaCode << ") ";
return output;
}

istream &operator>>(istream &input, const PhoneNumber &num){
input >> setw(4) >>num.areaCode;
return input;
}

int main(){
PhoneNumber phone;

cout << " Enter phone number ";

cin >> phone;

cout << phone << endl;
return 0;
}

[Jucato]

friend istream &operator>>(istream&, const PhoneNumber &);

Why is the PhoneNumber parameter a const? >> (stream insertion) needs to be able to modify the variable, doesn't it? That's probably the source of the error.

[supernick]

oh geez! how careless! thanks for pointing that out.