for(int i=0; i<512; i=i+2) //loops through the pairs of traders
{
    double r1 = rand();
    double r2 = rand();
    double max = RAND_MAX;
    double eta1 = r1/max;
    double eta2 = r2/max;
    // Generates random numbers eta1, eta2 between 0 and 1
    double P1 = order0[i].P_buy(t);
    double P2 = order0[i+1].P_buy(t);
 
    if( order0[i].getbuy()==1 )//if i has bought
    {
        // and if i+1 has bought as well
        if( order0[i+1].getbuy() == 1)
        {
            //then create new level of hierarchy
            order1[i] = trader1(order0[i], order0[i+1]);
        }
        else if( eta2 <= P2 )// if i+1 has not bought, will buy
        {
            order0[i+1].setbuy(1); //trader buys
            //then create new level of hierarchy
            order1[i] = trader1(order0[i], order0[i+1]);
        }
    }
    // at this point we know i has not bought
    else if( order0[i+1].getbuy() == 1)
    {
        if( eta1 <= P1 )// if i buys
        {
            //then create new level of hierarchy
            order1[i] = trader1(order0[i], order0[i+1]);
        }
    }
    // so neither has bought, see if they enter market
    else if ( eta1 <= P1 && eta2 <= P2 )// if both buy
    {
        order0[i].setbuy(1);
        order0[i+1].setbuy(1);
        //create new level of hierarchy
        order1[i] = trader1(order0[i], order0[i+1]);
    }
    else if ( eta1 <= P1 )//only i buys
    {
        order0[i].setbuy(1);
        order0[i+1].setinf(1);// i+1 is influenced
        order0[i+1].sett1(t);
    }
    else if ( eta2 <= P2 )// only i+1 buys
    {
        order0[i+1].setbuy(1);
        order0[i].setinf(1);// i is influenced
        order0[i].sett1(t);
    }
}