Why is only the first number being counted when storing user input into a vector?

Storing User Input into a Vector: A Comprehensive Guide

In this inquiry, a user is attempting to input multiple numbers into a vector and subsequently count them using a function call. The code provided below presents an issue where only the first number is counted:

<code class="cpp">template <typename T>
void write_vector(const vector<T>&amp; V)
{
   cout << "The numbers in the vector are: " << endl;
  for(int i=0; i < V.size(); i++)
    cout << V[i] << " ";
}

int main()
{
  int input;
  vector<int> V;
  cout << "Enter your numbers to be evaluated: " << endl;
  cin >> input;
  V.push_back(input);
  write_vector(V);
  return 0;
}</code>

The culprit lies in the fact that currently, only a single integer is being read from the user. To remedy this, a loop is required.

<code class="cpp">while (cin >> input)
    V.push_back(input);</code>

This loop continuously retrieves integers from standard input until there is no more input available. The input process concludes when cin detects the end of file (EOF) or encounters a non-integer value.

Alternatively, a sentinel value can be employed, which has the drawback of preventing the user from inputting that particular value. For instance:

<code class="cpp">while ((cin >> input) && input != 9999)
    V.push_back(input);</code>

In this scenario, input is collected until the user enters 9999 (or triggers another condition that renders cin invalid), upon which the loop terminates.

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