Passing std::vector items to variadic function

Question

I\'m using gcc 4.6. Assume that there is a vector v of parameters I have to pass to a variadic function f(const char* format, ...).

One approach of doing this is:

Answer 1

Judging by your own answer given, it sounds like you could make use of boost format.

Examples:

#include 
#include 
#include 
#include 
using namespace std;
using namespace boost;

template 
string formatted_str_from_vec(const T& v) {
    ostringstream fs;
    size_t count = 1;
    for (const auto& i : v) {
        if (&i != &v[0]) {
            fs << " ";
        }
        fs << '%' << count << '%';
        ++count;
    }
    format fmtr(fs.str());
    for (const auto& i : v) {
        fmtr % i;
    }
    // looks like fmtr("%1% %2% %3% %4%") % v[0] % v[1] etc.
    return fmtr.str();
}

int main() {
    cout << formatted_str_from_vec(vector({1, 2, 3, 4, 5, 6, 7, 8, 8, 10, 11, 12})) << endl;
    cout << formatted_str_from_vec(vector({"a", "b", "c"})) << endl;
    format test1("%1% %2% %3%");
    test1 % 1 % "2" % '3';
    cout << test1.str() << endl;
    format test2("%i %s %c");
    test2 % 1 % "2" % '3';
    cout << test2.str() << endl;
    format test3("%1% %2%");
    test3.exceptions(io::no_error_bits);
    test3 % 'g';
    cout << test3.str() << endl;
    format test4("%%1%% = %1%");
    test4 % "zipzambam";
    cout << test4.str() << endl;
}

// g++ -Wall -Wextra printvector.cc -o printvector -O3 -s -std=c++0x

Of course, none of that's necessary to just print out a vector.