Reference class member variables give an error "uninitialized reference" in constructor

Question

I have the following code:

#include<iostream>
using namespace std;

class Vec{
    private:
        int& var;
    public:
        Vec(int& tmp){
            var = tmp;
        }
};
int main(){
    int x = 10;
    Vec v1(x);
}

but it gives a compilation error:error: uninitialized reference member in ‘int&’ [-fpermissive]

How to resolve this?

You cannot initialize a reference variable of your class without an initializer list. — anas16, Jul 13 '22 at 19:13

score 5 · Answer 1 · answered Jul 13 '22 at 18:36

5

You should use an initializer list.

#include<iostream>
using namespace std;

class Vec{
    private:
        int& var;
    public:
        Vec(int& tmp) : var(tmp) {}
};
int main(){
    int x = 10;
    Vec v1(x);
}

answered Jul 13 '22 at 18:36

MikeCAT

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i am not sure what an initializer list means! can someone explain this or point to some good resource? Thanks in advance! – Jul 13 '22 at 18:38
@AJ: Do you know the difference between initialization and assignment? – Ben Voigt Jul 13 '22 at 18:42

Reference class member variables give an error "uninitialized reference" in constructor

1 Answers1