How to print out the contents of a vector?

Question

I want to print out the contents of a vector in C++, here is what I have:

#include 
#include 
#include 
#include         


        

Answer 1

I think the best way to do this is to just overload operator<< by adding this function to your program:

#include 
using std::vector;
#include 
using std::ostream;

template
ostream& operator<< (ostream& out, const vector& v) {
    out << "{";
    size_t last = v.size() - 1;
    for(size_t i = 0; i < v.size(); ++i) {
        out << v[i];
        if (i != last) 
            out << ", ";
    }
    out << "}";
    return out;
}

Then you can use the << operator on any possible vector, assuming its elements also have ostream& operator<< defined:

vector  s = {"first", "second", "third"};
vector    b = {true, false, true, false, false};
vector     i = {1, 2, 3, 4};
cout << s << endl;
cout << b << endl;
cout << i << endl;

Outputs:

{first, second, third}
{1, 0, 1, 0, 0}
{1, 2, 3, 4}