How do I write this very simple program?

Often, especially at the start of semesters, I get a lot of questions about how to write very simple programs. Typically, the problem to be solved is to read in a few numbers, do something with them, and write out an answer. Here is a sample program that does that:
PHP Code:
#include<iostream>
    #include<vector>
    #include<algorithm>
    
using namespace std;

    
int main()
    {
        
vector<doublev;

        
double d;
        while(
cin>>dv.push_back(d);    // read elements
        
if (!cin.eof()) {        // check if input failed
            
cerr << "format error\n";
            return 
1;    // error return
        
}

        
cout << "read " << v.size() << " elements\n";

        
reverse(v.begin(),v.end());
        
cout << "elements in reverse order:\n";
        for (
int i 0i<v.size(); ++icout << v[i] << '\n';

        return 
0// success return