g++ error: ‘vec’ does not name a type [duplicate]

Answer 1

Statements such as vec.push_back(42); are only allowed inside of functions. For example,

#include <iostream> 
#include <vector>

int main()
{
  using namespace std; 

  vector<int> vec; 

  vec.push_back(10);
  vec.push_back(5);
  vec.push_back(1);

  vector<int>::iterator itr1 = vec.begin();
  vector<int>::iterator itr2 = vec.end();

  for(vector<int>::iterator itr = itr1; itr != itr2; itr++){
    cout << *itr  << endl;  
  }

}