C ++: how to create a vector that already contains elements

Question

Possible duplicate:
C ++: The easiest way to initialize an STL vector with hard-coded elements
How to initialize a vector in C ++

I was wondering if there is a way to make a vector with declared elements.

Instead of doing:

vector< int > v; v.push_back(3); v.push_back(5); v.push_back(1); 

etc., where v = {3,5,1},

I want to create a vector that already contains elements such as:

 vector< int > v = {3,5,1}; 

Because a lot of work inserts each number into a vector. Is there a shortcut for this?

Answer 1

C ++ 11 supports exactly the syntax you suggest:

 vector< int > v = {3,5,1}; 

This function is called uniform initialization .

In previous versions of the language, there is no “pleasant” way.

Answer 2

You can use boost::assign

 std::vector<int> v = boost::assign::list_of(3)(5)(1); 

Answer 3

You can do in C ++ 11

 std::vector< int > v = {3,5,1}; 

as suggested by Greg Huglill or in C ++ 98

 static const int v_[] = {3,5,1}; std::vector<int> vec (v_, v_ + sizeof(v_) / sizeof(v_[0]) ); 

congratulations: fooobar.com/questions/15725 / ...

Answer 4

Yes in C ++ 11 you can do

std :: vector v {1,2,3,4};

you can create multiple elements of the same value via constructor in C ++ 98

 std::vector<int> v (5, 6); //6 6 6 6 6 

if you don't have C ++ 11, you can create some kind of push back object

 #include <vector> struct pb{ std::vector<int>& v_; pb(std::vector<int>& v) : v_(v){}; pb& operator+(int i) { v_.push_back(i); return *this; } }; int main() { std::vector<int> d; pb(d)+4+3; } 

Answer 5

C ++ 11 has such a function; most compilers support it.

To enable in gcc:

g ++ -std = gnu ++ 0x

VS2010 supports it out of the box, I think