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#include <iostream>
#include <vector>
#include <functional>
using namespace std;
template<typename LHS, typename RHS, template<typename> class Operation>
struct BinExpr;
template<typename RHS>
struct BasicType
{
typedef RHS ObjType;
};
template<typename LHS, typename RHS, template<typename> class Operation>
struct BasicType<BinExpr<LHS, RHS, Operation>>
{
typedef typename BinExpr<LHS, RHS, Operation>::ObjType ObjType;
};
template<typename LHS, typename RHS, template <typename> class Operation>
struct BinExpr
{
typedef typename BasicType<RHS>::ObjType ObjType;
typedef typename ObjType::value_type value_type;
LHS const &d_lhs;
RHS const &d_rhs;
BinExpr(LHS const &lhs, RHS const &rhs)
:
d_lhs(lhs),
d_rhs(rhs)
{}
size_t size() const
{
return d_lhs.size();
}
value_type operator[](size_t ix) const
{
static Operation<value_type> operation;
return operation(d_lhs[ix], d_rhs[ix]);
}
operator ObjType() const
{
ObjType retVal;
for (size_t ix = 0; ix != d_lhs.size(); ++ix)
retVal.push_back((*this)[ix]);
return retVal;
}
};
template<typename LHS, typename RHS>
BinExpr<LHS, RHS, plus> operator+(LHS const &lhs, RHS const &rhs)
{
return BinExpr<LHS, RHS, plus>(lhs, rhs);
}
int main()
{
vector<int> one {1, 2, 3};
vector<int> two {4, 5, 6};
vector<int> three = one + two + (one + two);
auto four = one + two + (one + two);
auto z = "hello world";
cout << z << '\n';
cout << three[0] << ' ' << three[2] << '\n';
cout << four[0] << ' ' << four[2] << '\n';
}
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