Return a number as reference parameter

Question

I am a freshman college student learning C++. I want to return the number as a reference parameter in a template function. Btwhen I debug, nothing appears there. Please help the rookie!

#include <iostream>
using namespace std;
template<class T>
T &Input(T a) {
    cout << "Enter a positive number";
    int n = 0;
    T number = 0;
    do {
        cin >> number;
        if (number >= 0) {
            return number;
        }
        else {
            cout << "Your input is invalid!"<<"\n";
            cin >> number;
        }

    } while (n < 3);
    return false;
}