find sum of 2 ints

#include <unordered_set>
#include <iostream>

template <class T, unsigned size>
bool findSum(T (&a)[size], T v, T& i1, T& i2) {
    std::unordered_set<T> m;

    for (unsigned i = 0; i < size; ++i) {
        auto it = m.find(a[i]);
        if (it == m.end()) {
            m.insert(v - a[i]);
        } else {
            i1 = a[i];
            i2 = v - *it;
            return true;
        }
    }

    return false;
}

int main() {

    int A[] = {6,2,5,9}; 
    int i1 = 0, i2 = 0;
    int v = 11;
    if (findSum(A, v, i1, i2)) {
        std::cout << i1 << "+" << i2 << "=" << v << std::endl;
    }
}