Variable number of parameters in function in C++

Question

How I can have variable number of parameters in my function in C++.

Analog in C#:

public void Foo(params int[] a) {
    for (int i = 0; i < a.Leng         


        

Answer 1

Aside from the other answers, if you're just trying to pass an array of integers, why not:

void func(const std::vector& p)
{
    // ...
}

std::vector params;
params.push_back(1);
params.push_back(2);
params.push_back(3);

func(params);

You can't call it in parameter, form, though. You'd have to use any of the variadic function listed in your answers. C++0x will allow variadic templates, which will make it type-safe, but for now it's basically memory and casting.

You could emulate some sort of variadic parameter->vector thing:

// would also want to allow specifying the allocator, for completeness
template  
std::vector gen_vec(void)
{
    std::vector result(0);
    return result;
}

template  
std::vector gen_vec(T a1)
{
    std::vector result(1);

    result.push_back(a1);

    return result;
}

template  
std::vector gen_vec(T a1, T a2)
{
    std::vector result(1);

    result.push_back(a1);
    result.push_back(a2);

    return result;
}

template  
std::vector gen_vec(T a1, T a2, T a3)
{
    std::vector result(1);

    result.push_back(a1);
    result.push_back(a2);
    result.push_back(a3);

    return result;
}

// and so on, boost stops at nine by default for their variadic templates

Usage:

func(gen_vec(1,2,3));