Cannot Bind Non-Const Lvalue Reference to Rvalue: A Resolution

The given code snippet encountered an error while initializing an object of class Foo within the constructor of class Bar. The error message indicates that a non-const lvalue reference (Foo f) is being bound to an rvalue (the result of calling genValue()).

In C , non-const reference parameters can only refer to named variables (lvalues). However, the result of genValue() is a temporary value (rvalue). To resolve this issue, we need to pass the value of genValue() by value (int).

class Foo {
public:
    Foo(int x) {
        this->x = x;
    }
private:
    int x;
};

class Bar {
public:
    Bar(): f(genValue()) {
    }
private:
    Foo f;

    int genValue() {
        int x;
        // do something ...
        x = 1;
        return x;
    }
};

By changing the constructor argument to int, we can now initialize the Foo object within the constructor scope without any errors.