#include <vector> 
 
struct Foo { float v; };
struct Bar { int i; };
struct Tar { float p, q; };
 
void Convert(const Foo& x, Bar& y) { y.i = static_cast<int>(x.v); }
void Convert(const Tar& x, Foo& y) { y.v = x.p + x.q; }
 
template<typename X, typename Y>
void Convert(const std::vector<X>& cx, std::vector<Y>& cy) {
   cy.resize(cx.size());
   for(std::size_t i=0; i<cx.size(); i++) {
     Convert(cx[i], cy[i]);
   }
}
 
int main() {
    std::vector<Foo> cx(10);
    std::vector<Bar> cy;
    Convert(cx, cy);
}

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