Anonymous members

struct Example {
    struct {
        int inner_b;
    };
    
    int outer_b;
    
    //The anonymous struct's members are accessed as if members of the parent struct
    Example() : inner_b(2), outer_b(4) {
        inner_b = outer_b + 2;
    }
};

Example ex;

//The same holds true for external code referencing the struct
ex.inner_b -= ex.outer_b;