map and zip function in c++

mapzip.cpp

// Example program
#include <iostream>
#include <string>
#include <vector>

using std::vector;

template<typename P, typename Iterator, typename Mapper>
void map(Iterator current, Iterator end, Mapper mapper, vector<P>& ret) {
    if (current == end) return;
    ret.push_back(mapper(*current));
    map(++current, end, mapper, ret);
};

template<typename IteratorA, typename IteratorB, typename Zipper, typename P>
void zip(IteratorA a, IteratorA aEnd, IteratorB b, IteratorB bEnd, Zipper zipper, vector<P>& ret) {
    if (a == aEnd || b == bEnd) return;
    ret.push_back(zipper(*a, *b));
    zip(++a, aEnd, ++b, bEnd, zipper, ret);
}

int main()
{
    vector<int> a{1,2,3,4,5};
    vector<int> ret;
    map(a.begin(), a.end(), [](int i){return i*i;}, ret);
    
    vector<float> ret2;
    zip(a.begin(), a.end(), ret.begin(), ret.end(), [](int a, int b){ return (float)a + (float)b;}, ret2);
    
    for (auto& i : ret2) {
        std::cout << i << ",";
    }
}