[英]how pass an array as parameter, and the array is defined in the parameters in c++
我正在將ac#編寫的程序轉換為c ++代碼。 我有一個ac#函數聲明,例如:
// c# function declaration
int DerivationFunc(int id, params BasicFeature[] args);
所以我將其轉換為c ++
// c++ function declaration
int DerivationFunc(int id, BasicFeature* args, int argsNum); // argsNum denotes the size of the array
現在調用函數時出現問題。 在c#中,我可以使用參數中的數組定義來調用該函數:
// c# function calling
DerivationFunc(16, new BasicFeature[] {query, keyword});
那么如何在C ++中做到這一點呢?
// c++ function calling
DerivationFunc(16, /*something like BasicFeature[] {query, keyword} but with the right syntax*/, 2);
您可以重寫該函數以采用std :: initializer_list :
#include <initializer_list>
#include <iostream>
struct BasicFeature {
} query, keyword;
int DerivationFunc(int id, std::initializer_list<BasicFeature> args)
{
std::cout << args.size() << " element(s) were passed.\n";
return id;
}
int main()
{
DerivationFunc(42, { query, keyword });
}
如果您不被允許使用std::initializer_list
,我可能會建議您使用一些難看的技巧:
#include <vector>
#include <iostream>
enum BasicFeature {
query,
keyword
};
template<typename T>
class init_list
{
public:
init_list &operator<<( typename T::value_type value )
{
m_list.push_back(value);
}
operator const T() const { return m_list; }
private:
T m_list;
};
void DeriviationFunc( int id, const std::vector<BasicFeature> &args )
{
std::cout << id << std::endl;
std::cout << args.size() << std::endl;
std::cout << args[0] << std::endl;
}
int main()
{
DeriviationFunc(16, init_list<std::vector<BasicFeature> >() << query << keyword);
return 0;
}
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