Input validation

gistfile1.cpp

#include <iostream>
#include <limits>

using namespace std;

template<typename T>
bool valid_input(istream &stream, T &value)
{
    bool good = true;

    stream >> value;

    if (!stream || stream.peek() != '\n')
    {
        good = false;
    }

    if (!good)
    {
        stream.clear();
        stream.ignore(numeric_limits<streamsize>::max(), '\n');
    }

    return good;
}

int main()
{
    int n;
    while (cout << "Enter a fucking number: ", !valid_input(cin, n))
    {
        cout << "Not a fucking number!" << endl;
    }

    cout << "Your number was " << n << endl;
    return 0;
}