wtfunctional/examples/03_cpp.cpp

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#include <iostream>
#include <vector>
#include <algorithm>
#include <numeric>
int main() {
std::vector<int> a{1,2,3,4};
std::vector<int> b{5,6,7,8};
// result vector
std::vector<double> c(a.size(), 0);
// double
std::for_each(a.begin(), a.end(), [](int &n){ n*=2;});
std::cout << "Double:" << std::endl;
for (auto const &i: a){ std::cout<<i<<" ";}
std::cout << std::endl;
// Reset a
a = {1,2,3,4};
// inverse
std::transform(a.begin(), a.end(),
c.begin(),
[](int i){return 1.0/i;});
std::cout << "Multiplicative inverse:" << std::endl;
for (auto const &i: c){ std::cout << i << " ";}
std::cout << std::endl;
// reziprocal sum
std::transform(a.begin(), a.end(),
b.begin(), c.begin(),
[](int i, int j){return 1.0/(1.0/i + 1.0/j);});
std::cout << "Reziprocal sum:" << std::endl;
for (auto const &i: c){ std::cout << i << " ";}
std::cout << std::endl;
// Folds
int sum = std::accumulate(a.begin(), a.end(), 0);
int diff = std::accumulate(a.begin(), a.end(), 15, std::minus<int>());
int mult = std::accumulate(a.begin(), a.end(), 1,
[](int a, int b)->int { return a * b; });
std::cout << "Sum: " << sum
<< "\nDiff from 15: " << diff
<< "\nProd: " << mult
<< std::endl;
return 0;
}