std::vector vs. C-style arrays

[etaoin]

I hope that the stl gurus can help me with this...

Consider the following: In my current project, a team member implemented code such as the following:

int*    m_timeArray;
string* m_nameArray;
double* m_valueArray;

// Dynamically allocate space for the arrays here...

for(int i=0; i < numElements; i++)
{
  m_timeArray[i] = someTime;
  m_nameArray[i] = someName;
  m_valueArray[i] = someValue;
}

As these C-style arrays are actually representing an array of objects (each consisting of a time, a name and a value, in this simplified example), I suggested to

• create a class which has time, name and value as members, and
• use a std::vector instead of a C array.

Something along the lines of:

class Element
{
public:
  Element(int time, const char* pName, double value);
  virtual ~Element();

private:
  int    m_time;
  string m_name;
  double m_value;
};

vector<Element> elements;

Now this is a very performance critical part of the code, and the other team member (which is a hardcore C-programmer and performance fetishist anyway, who mistrusts stl and C++ in general) argued that it wouldn't be possible with this design to add elements to the array with the same efficiency. More specifically, code like

elements.push_back(Element(someTime, someName, someValue));

will of course create a temporary Element object and invoke Element's default copy constructor, which is obviously more costly than the C code. However, I made two bold statements saying that

1. when switching from a C array to std::vector, very little changes will be necessary to the existing code (which is not true, as I can't add elements to the array with something like elements[i] = ..., but I will have to use push_back - right?)
2. That it is possible to use a std::vector of elements with the same efficiency as using multiple C arrays (like in the original code).

Here I'm stuck - it seems that I can't add elements to the vector without creating a temporary object, and therefore effectively copying the data twice. Any ideas?