[c++] What is the simplest way to convert array to vector?

What is the simplest way to convert array to vector?

void test(vector<int> _array)
{
  ...
}

int x[3]={1, 2, 3};
test(x); // Syntax error.

I want to convert x from int array to vector in simplest way.

Personally, I quite like the C++2011 approach because it neither requires you to use sizeof() nor to remember adjusting the array bounds if you ever change the array bounds (and you can define the relevant function in C++2003 if you want, too):

#include <iterator>
#include <vector>
int x[] = { 1, 2, 3, 4, 5 };
std::vector<int> v(std::begin(x), std::end(x));

Obviously, with C++2011 you might want to use initializer lists anyway:

std::vector<int> v({ 1, 2, 3, 4, 5 });

Pointers can be used like any other iterators:

int x[3] = {1, 2, 3};
std::vector<int> v(x, x + 3);
test(v)

One simple way can be the use of assign() function that is pre-defined in vector class.

e.g.

array[5]={1,2,3,4,5};

vector<int> v;
v.assign(array, array+5); // 5 is size of array.

You're asking the wrong question here - instead of forcing everything into a vector ask how you can convert test to work with iterators instead of a specific container. You can provide an overload too in order to retain compatibility (and handle other containers at the same time for free):

void test(const std::vector<int>& in) {
  // Iterate over vector and do whatever
}

becomes:

template <typename Iterator>
void test(Iterator begin, const Iterator end) {
    // Iterate over range and do whatever
}

template <typename Container>
void test(const Container& in) {
    test(std::begin(in), std::end(in));
}

Which lets you do:

int x[3]={1, 2, 3};
test(x); // Now correct

(Ideone demo)