#include <iostream> using namespace std; struct Apple { int weight; int color; }; struct Car { int weight; int wheels; int color; }; int *color(Apple *a) { return (int *)((char *)a + 4); } int *color(Car *a) { return (int *)((char *)a + 8); } template<typename T> void foo(T *a, int v) { //a->color = 71; *color(a) = v; } int main() { auto car = Car {}; auto apple = Apple {}; foo(&car, 1); foo(&apple, 2); cout << car.color << " " << apple.color << "\n"; return 0; }