access to a class from other function

#include <iostream>

using namespace std;

class test
{
    public:
    string a;
    string def();
};

string test::def()
{

    string a="abc";
    return a;
}

int main()
{

    test ob;
    ob.a=ob.def();
    cout << ob.a<< endl;
    return 0;
}