Thread: my professior gave us an example program for a fiter.. but I can't get it to work...

my professor gave us an example program for a filter.. but I can't get it to work...
This is my 1st time using C++ and before we where learning C... so I can't easily see why it doesn't work.... this is an example and shouldn't have errors but ya.. it does so can anyone help me? thanks

Code:

#include <iostream>
using namespace std;

int main()
{
    int i, numpts;
    double input[25]; //store values for filtering
    cout << "enter number of points: ";
    cin >> numpts;
    for (int i = 0; i < numpts; i++)
    {
        cout << "Enter a point: ";
        cin >> input[i];
    }
    double output[25]; //store filtered results
    double alpha = .5;// 0 < alpha 1
    output[0] = input[0];
    for (int i = 1; i < numpts; i++)
        output[i] = alpha*input[i]+(1-alpha)*output[i-1];
    for (int i = 0; i < numpts; i++)
    {
        cout << "Output " <<i << " is " << output[i];
        cout << "\n";
    }
    return 0;
}