What happens when you attempt to compile and run the following code?
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
class B { int val;
public:
B(int v):val(v){}
int getV() const {return val;} bool operator < (const B & v) const { return val<v.val;} }; ostream & operator <<(ostream & out, const B & v) { out<<v.getV(); return out;}

template<class T>struct Out {
ostream & out;
Out(ostream & o): out(o){}
void operator() (const T & val ) { out<<val<<" "; } };

int main() {
B t1[]={3,2,4,1,5};
B t2[]={6,10,8,7,9};
vector<B> v1(10);
sort(t1, t1+5);
sort(t2, t2+5);
merge(t1,t1+5,t2,t2+5,v1.begin());
for_each(v1.begin(), v1.end(), Out<B>(cout));cout<<endl; return 0;
}
Program outputs: