Прога на Си на среднее арифмитесечкое постоянных.

float dataProcessing(FILE *fin) {
    long x,y,summ;
    int counter = 1;
    float result;
    if (fscanf(fin,"%lf",&y)!=1) return -1;

    while(fscanf(fin,"%lf",&x) = 1) {
        if (x!=y) {
            summ += y;
            y = x;
            counter++;
            continue;
        } else {
            y = x;
        }
    }
    result = summ / counter;
    return result;
}