#include <stdarg.h>
#include <iostream>

int sum( const int& count, ... )
{
    va_list args;
    va_start( args, count );

    int result = 0;
    for ( int i = 0; i < count; i++ )
        result += va_arg( args, int );
    return result;
}

int main()
{
    std::cout << sum( 3, 1, 2, 3 );
    
    return 0;
}

The restrictions that ISO C places on the second parameter to the va_start() macro in header <stdarg.h> are different in this International Standard. The parameter parmN is the identifier of the rightmost parameter in the variable parameter list of the function definition (the one just before the ...). [Footnote: Note that va_start is required to work as specified even if unary operator& is overloaded for the type of parmN.] If the parameter parmN is declared with a function, array, or reference type, or with a type that is not compatible with the type that results when passing an argument for which there is no parameter, the behavior is undefined.

SaZ>#include <stdarg.h>
SaZ>#include <iostream>

SaZ>int sum( const int& count, ... )
SaZ>{
SaZ>    va_list args;
SaZ>    va_start( args, count );

SaZ>    int result = 0;
SaZ>    for ( int i = 0; i < count; i++ )
SaZ>        result += va_arg( args, int );
SaZ>    return result;
SaZ>}

SaZ>int main()
SaZ>{
SaZ>    std::cout << sum( 3, 1, 2, 3 );
    
SaZ>    return 0;
SaZ>}
SaZ>

void PrintFloats ( int amount, ...)
{
int i;
double val;
printf ("Floats passed: ");
va_list vl;
va_start(vl,amount);
for (i=0;i<amount;i++)
{
val=va_arg(vl,double);
printf ("\t%.2f",val);
}
va_end(vl);
printf ("\n");
}

int main ()
{
PrintFloats (3,3.14159,2.71828,1.41421);
return 0;
}