No 1:

I noticed in a previous post that there was a debate about the use of cout and std::cout. I feel like I partially understand this and sense that it has something to do with <iostream.h> vs <iostream> and 'including namespace std' and the ANSI C++ standards.

Does this make sense and is there any chance of a brief explanation of this.... becuase in the textbooks I'm using, they all seem to refer to cout rather than std::cout.



No 2:

I'm trying to write a program to do simple statistics (mean, standard deviation). At the moment I'm using arrays to store the data set. I've not had a problem as long as I am able to say how many numbers there are in the data set, e.g

Code:
int n;
cout << "How many numbers in the data set? ";
cin >> n;

double dataSet[n]; 
 //But what to do if I don't know what 'n' is?

for (int counter = 0; counter !=n; counter++)
{
    cout << "\nNumber " << (counter +1) << ": ";
    cin >> dataSet[counter];
}

etc
But what should I do if I don't know how many should be in the data set (i.e. what happens when I don't know what 'n' is before I input the data? I'm sure this isn't a new question. Is using <fstream> the solution?