va_listのサンプル

va_list_sample.cpp

#include <cstdio>
#include <cstdarg>

template<typename T>
T sumN(unsigned int n, ...)
{
    va_list vl;
    va_start(vl, n);
    
    T sum = 0;
    for (unsigned int i=0; i < n; ++i)
        sum += va_arg(vl, T);
    
    va_end(vl);
    
    return sum;
}

int main()
{
    printf("%d\n", sumN<int>(4, 3, 5, 8, 9));       // 25
    printf("%g\n", sumN<double>(3, 0.4, 2.4, 6.1)); // 8.9
    return 0;
}