Hello, I have some weird problem with this code.
The problem is that when I use >> to read data a text file to vector. It will only add the first double and discard the rest. Anyway if I use array instead of vector it works fine. Anyone know what the problem can be? I've used cout to check whetever it sends in correct data or not. And it does send in correct data.

#include <iostream>
#include <string>
#include <vector>
using namespace std;

struct Demo {
    string name;
    double points;
    vector<double> test;
//    double test[2];
};

istream& operator>> (std::istream& in, Demo &d);
istream& operator>> (std::istream& in, vector<double> d);
//istream& operator>> (istream& in, double d[]);
int main()
{
    vector<Demo> d;
    Demo tmp;
    while(cin >> tmp) {
        d.push_back(tmp);
    }
    cout << d[0].name << ", " << d[0].points << ", " << d[0].test[0] << ", " << d[0].test[1] << endl;
    cout << d[1].name << ", " << d[1].points << ", " << d[1].test[0] << ", " << d[1].test[1] << endl;
    cout << d[2].name << ", " << d[2].points << ", " << d[2].test[0] << ", " << d[2].test[1] << endl;
    cout << d[3].name << ", " << d[3].points << ", " << d[3].test[0] << ", " << d[3].test[1] << endl;
    cout << d[4].name << ", " << d[4].points << ", " << d[4].test[0] << ", " << d[4].test[1] << endl;
    cout << d[5].name << ", " << d[5].points << ", " << d[5].test[0] << ", " << d[5].test[1] << endl;
    return 0;
}

istream& operator>> (std::istream& in, Demo &d) {
    getline(in, d.name);
    in >> d.points;
    in >> d.test;
    return in;
}
std::istream& operator>> (std::istream& in, vector<double> d) {
    double x;
    d.clear();
    for(int i = 0; i < 2; i++) {
        in >> x;
        d.push_back(x);
    }
    in.ignore();
    return in;
}
//istream& operator>> (istream& in, double d[]) {
//    for(int i = 0; i < 2; i++) {
//        in >> d[i];
//    }
//    in.ignore();
//    return in;
//}

the text file I use contains

Mario Pizza
2.3 159.9 1
Luigi Kebab
2.6 169.5 2
Princess Peach
2.6 169.5 3
Link Hylia
2.6 169.5 4
Zelda Hyrule
2.6 169.5 5

Pass the vector by reference just like you already pass the Demo object.

istream& operator>> (std::istream& in, vector<double> & d);
std::istream& operator>> (std::istream& in, vector<double> & d)

Maybe read about References

hi,
i tried that before, but the problem with that is it will add all values into same vector<double> test. That's not want I wanted, I want to have the first double value in points, and the following two double values into unique vector<double> test for each user

hi,
i tried that before, but the problem with that is it will add all values into same vector<double> test.

When you tried that and noticed that problem, are you sure that you did not have the d.clear(); call. Because the clear(), as you now have it, will empty the vector (of the tmp Demo object) so you'll not be accumulating the values in the vectors.

Maybe I'm not fully understanding you, because I'd still say that if you pass the vector by reference, you'll get what you want. I.e.

I want to have the first double value in points, and the following two double values into unique vector<double> test for each user

Yes I removed clear(); when I tried it before. Anyway it works now when I put it back :)

Thanks alot for the help!

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