#include <numeric>
#include <iostream>
#include <vector>
int main() {
std::vector<double> v{1.0, 2.0, 3.0, 4.0, 5.0, 6.0};
double avg = std::accumulate(std::begin(v), std::end(v), 0.0) / (std::end(v) - std::begin(v));
std::cout << avg << std::endl;
return 0;
}
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