#include <vector>
#include <iostream>
 
int main(void)
{
std::vector<int> container = {11,3,5,6,200};
for (size_t i=0; i<container.size(); ++i)
{if (container [i]==5)
{
std::cout << "position: " << i+1 << std::endl;
break;
}
}
return 0;
}