Description : The function returns a pointer to the first element in the array which is used internally by the vector. It doesn't accept any parameters.
Example:
int main(){
//vector initialisation
std::vector<int> v = { 1, 2, 3, 4, 5 };
//memory pointer pointing to the first element
int* pos = v.data();
// prints the vector
std::cout << "The vector elements are: ";
for (int i = 0; i < v.size(); ++i)
std::cout << *pos++ << " ";
return 0;
}