Why it prints unexpected values?

Question

#include <iostream>

using namespace std;

class calculator {
public:
    int n1, n2;

    friend void setNumbers(calculator v);
    friend void getNumbers(calculator v);
};

void setNumbers(calculator v) {
    cin >> v.n1 >> v.n2;
}

void getNumbers(calculator v) {
    cout << v.n1 << ' ' << v.n2 << '\n';
}

int main() {
    calculator calc;
    setNumbers(calc);
    getNumbers(calc);
    return 0;
}

When I call getNumbers function, it prints totally different values which I didn't input. For example when I input 3 6 , it prints 0 1 , while I expected 3 6 . What could be wrong?

Answer 1

Passing the object without a reference won't change the values of your calculator object when you expect them to be initialized by your input values after a call to setNumbers . Instead they'll have garbage values since they are not initialized for getNumbers .

Pass the calculator objects via reference by using & as mentioned in the comments and you're good to go.

class calculator 
{
    public:
    int n1, n2;
    friend void setNumbers(calculator &v);
    friend void getNumbers(calculator &v);

};

void setNumbers(calculator &v) {
    cin >> v.n1 >> v.n2;
}

void getNumbers(calculator &v) {
    cout << v.n1 << ' ' << v.n2 << '\n';
}