sum() [2/2]

template<concepts::product_type T, typename Value>

auto kumi::sum ( T && t, Value init )

inlinenodiscardconstexpr

Computes the sum of all elements.

On record types, this function operates on the underlying values, not on the fields themselves.

Parameters

t	Product type to operate on
init	Optional initial value of the sum

Returns

The value of get<0>(t) + ... + get<N-1>(t) + init

Helper type

namespace kumi::result
{
  template<product_type T, typename Value> struct sum;
 
  template<product_type T, typename Value>
  using sum_t = typename sum<T,Value>::type;
}

Computes the return type of a call to kumi::sum

Examples:

Tuple:

#include <kumi/kumi.hpp>
#include <iostream>
 
int main()
{
  auto t = kumi::tuple{2.,1,short{55},' '};
 
  std::cout << kumi::sum(t, 100) << "\n";
  std::cout << kumi::sum(t) << "\n";
}

Record:

#include <kumi/kumi.hpp>
#include <iostream>
 
int main()
{
  using namespace kumi::literals;
  auto r = kumi::record{"a"_id = 2.,"b"_id = 1,"c"_id = short{55},"d"_id = ' '};
 
  std::cout << kumi::sum(r, 100) << "\n";
  std::cout << kumi::sum(r) << "\n";
}