c++ generic programming with stuctures

alright so basically what i have is 2 structs that have varying number of members in them and i need to iterate through and send to a method. the only problem is is that this is not my code and i can only add to it not change existing things. i was wondering if there is a way to do this in 1 method instead of 1 method for every possibility.

example time

struct a
{
    string val1;
    double val2;
}; 

struct b 
{
    int val1;
    int val2;
    int val3;
}

template<typename T>
void func(T temp)
{
    //do work with all the variables in the struct
    //ie for(...blah...){cout<<blah<<endl};
}

i know there is no way to get the name of the variables in c++ but if there is a new way to do that i would also like to know how to do that.