Variadic function with recursion

I trying to write a recursive function with variadic parameters for copy my data. But this function copy only last parameter. What I do wrong?

This is output:

13 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

12 0 0 0 0 0 0 0 0 0 0 0


Best regards.

#include <iostream>
#include <cstdint>
#include <cstring>
using namespace std;

void copy_data(unsigned char* ar, unsigned& offset, int data)
std::memcpy(ar + offset, (void*)&data, sizeof(data));
offset += sizeof(data);


template<class... Args>
void copy_data(unsigned char* ar, unsigned& offset, int data, Args... args)
if ((sizeof...(Args)) == 0)
copy_data(ar, offset, data);

copy_data(ar, offset, args...);


void printf_data(const unsigned char* ar, int s)
for (int i = 0; i < s; ++i)
std::cout << (int)ar[i] << " ";

std::cout<<"n";


int main()
unsigned char *arr0 = new unsigned char[16];
unsigned char *arr1 = new unsigned char[12];

int p0 = 10;
int p1 = 11;
int p2 = 12;
int p3 = 13;

unsigned offset = 0;

copy_data(arr0, offset, p0, p1, p2, p3);

offset = 0;
copy_data(arr1, offset, p0, p1, p2);

printf_data(arr0, 16);
printf_data(arr1, 12);

delete arr1;
delete arr0;
return 0;



UPDATE: corrected function

template <typename T>
void copy_data(unsigned char* ar, unsigned& offset, T data)
std::memcpy(ar + offset, (void*)&data, sizeof(data));
offset += sizeof(data);


template <typename T, typename... Args>
void copy_data(unsigned char* ar, unsigned& offset, T data, Args... args)
copy_data(ar, offset, data);
copy_data(ar, offset, args...);



1 Answer
1

The recursion only outputs anything when:

if ((sizeof...(Args))==0)
copy_data(ar, offset, data);



and that only happens after you strip every argument except the last off.

Remove the if clause.

if

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