int fromBar = the bar from where you start the calculation;
double minBalance = find the minimal balance for the period;
double sumX  = 0;
double sumY  = 0;
double sumXX = 0;
double sumYY = 0;
double sumXY = 0;

int count = 0;
for (int i = 0; i <= count_of_orders; i++) {
    if (Close a position) {
        int    x = oreder[0].bar - fromBar + 1;
        double y = oreder[0].balance - minBalance + 1;
        sumX += x;
        sumY += y;
        sumXX += x * x;
        sumYY += y * y;
        sumXY += x * y;
        count++;
    }
}

if (count < 2) {
    return 0;
}

double r  = (count * sumXY - sumX * sumY) / Math.sqrt(count * sumXX - sumX * sumX) / Math.sqrt(count * sumYY - sumY * sumY);
double r5 = Math.pow(r, 5);

return 100 * r5;