Why doesn't this vector print?

Question

The compile error says it was not declared in this scope, it does not name a type, expected ;

#include <iostream>
#include <vector>

using namespace std;

int main()
{
    vector<int> vec;

    vec.push_back(1);
    vec.push_back(3);
    vec.push_back(5);

    for (auto it = vec.begin(); it != vec.end(); ++it) {
         cout << *it << endl;
    }

    cout << "size: " << vec.size() << endl;

    return 0;
}

Works fine: http://ideone.com/qVFl6p. Did you specify -std=c++11 ? — hmjd, Jan 30 '13 at 23:05
Yes thank you, I had it set before must of not saved, it works now though! — Sal Rosa, Jan 30 '13 at 23:08
I indented it like that because I was having trouble posting the code. — Sal Rosa, Jan 30 '13 at 23:39

score 2 · Answer 1 · edited May 23 '17 at 12:04

2

As commented, you need to specify the -std=c++11 flag when compiling.

Just to mention an alternative syntax for iterating, the range-for statement:

for (auto& i: vec)
{
    std::cout << i << std::endl;
}

and for populating a vector with initial values using uniform initialization:

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

Also see Why is "using namespace std" considered bad practice?

edited May 23 '17 at 12:04

Community

1
1

answered Jan 30 '13 at 23:10

hmjd

117,013
19
199
247

why auto& and not just auto? I'm new to C++. – Sal Rosa Jan 30 '13 at 23:38
1

@SalRosa to take a reference to the element of the container. It really should be ``const auto&``, since you are not modifying the element inside the loop. – juanchopanza Jan 30 '13 at 23:50

Why doesn't this vector print?

1 Answers1