trotFunky/tsp_cpp
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Better decltype for Polynomial::add return type

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This commit is contained in:
trotFunky 2019-05-14 12:43:53 +02:00
parent f51d403b8e
commit 004142f85a
1 changed files with 5 additions and 4 deletions
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9
snippets/Polynomial.tpp
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@ -35,7 +35,7 @@ public:
bool equals(const Polynomial<T1>&) const;
template <typename T1>
auto add(const Polynomial<T1>& operand) const -> Polynomial<decltype(static_cast<T>(0) + operand[0])>;
auto add(const Polynomial<T1>& operand) const -> Polynomial<decltype(T{} + T1{})>;
template <typename T1>
friend std::ostream& operator<<(std::ostream&, const Polynomial<T1>&);
@ -62,6 +62,7 @@ private:
template<typename T>
Polynomial<T>::Polynomial()
{
// Not bad, but could be better with C++20. Not that useful either
static_assert(std::is_arithmetic<T>::value,"Polynomial must be of an arithmetic type!");
factors = {0};
}
@ -197,7 +198,7 @@ bool Polynomial<T>::equals(const Polynomial<T1>& operand) const
template<typename T>
template<typename T1>
auto Polynomial<T>::add(const Polynomial<T1>& operand) const -> Polynomial<decltype(static_cast<T>(0) + operand[0])>
auto Polynomial<T>::add(const Polynomial<T1>& operand) const -> Polynomial<decltype(T{} + T1{})>
{
bool isLargest = true;
@ -212,7 +213,7 @@ auto Polynomial<T>::add(const Polynomial<T1>& operand) const -> Polynomial<declt
largestSize = operand.factors.size();
}
std::vector<decltype(static_cast<T>(0)+operand[0])> resultPolynomial = {};
std::vector<decltype(T{} + T1{})> resultPolynomial = {};
resultPolynomial.reserve(largestSize);
for(int i = 0;i<smallestSize;i++)
@ -225,7 +226,7 @@ auto Polynomial<T>::add(const Polynomial<T1>& operand) const -> Polynomial<declt
resultPolynomial.push_back((isLargest ? factors[i] : operand[i]));
}
return Polynomial<decltype(static_cast<T>(0)+operand[0])>(resultPolynomial);
return Polynomial<decltype(T{} + T1{})>(resultPolynomial);
}
////////////////////