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

Using std::copy but without extra trailing separator

An alternative/modified approach using std::copy (as originally used in @JoshuaKravtiz answer) but without including an additional trailing separator after the last element:

#include 
#include 
#include 
#include 

template 
void print_contents(const std::vector& v, const char * const separator = " ")
{
    if(!v.empty())
    {
        std::copy(v.begin(),
                  --v.end(),
                  std::ostream_iterator(std::cout, separator));
        std::cout << v.back() << "\n";
    }
}

// example usage
int main() {
    std::vector v{1, 2, 3, 4};
    print_contents(v);      // '1 2 3 4'
    print_contents(v, ":"); // '1:2:3:4'
    v = {};
    print_contents(v);      // ... no std::cout
    v = {1};
    print_contents(v);      // '1'
    return 0;
}

---

Example usage applied to container of a custom POD type:

// includes and 'print_contents(...)' as above ...

class Foo
{
    int i;
    friend std::ostream& operator<<(std::ostream& out, const Foo& obj);
public:
    Foo(const int i) : i(i) {}
};

std::ostream& operator<<(std::ostream& out, const Foo& obj)
{
    return out << "foo_" << obj.i; 
}

int main() {
    std::vector v{1, 2, 3, 4};
    print_contents(v);      // 'foo_1 foo_2 foo_3 foo_4'
    print_contents(v, ":"); // 'foo_1:foo_2:foo_3:foo_4'
    v = {};
    print_contents(v);      // ... no std::cout
    v = {1};
    print_contents(v);      // 'foo_1'
    return 0;
}