I've got big problems with a for loop into another for loop.
I report below the piece of code.

---------------------
sgenrand(rand() %(RAND_MAX+1)); // Random seed of the pseudorandom sequence
for (int i=0;  i< no_steps; ++i)
        {
          double y = genrand1(); // random numbers
          S_t = S_t * exp(R + SD * cndev(y));
          prices[i]=S_t;   // The array

        };

    //..... some manipulations
    double price = sum_c_max* (exp (-r*time));  // The result
---------------------

I'd like to calculate "double price" n times with different random numbers
in order to obtain the average of such values.
I thought that i needed to put this process into another for loop.
But i don't know how to do that.
I did as follows, but that gives wrong results:

for (int j=0;  j< no_paths; ++j)
{
    sgenrand(rand() %(RAND_MAX+1));

   for (int i=0;  i< no_steps; ++i)
          {

            double y = genrand1();
            S_t = S_t * exp(R + SD * cndev(y));
            prices[i]=S_t;

          };

    m = *max_element(prices.begin(),prices.end()); // the max value of the
array
    tx = prices.back(); // the last value
    if (m > bar)
    sum_c_max  += max(0.0, tx - X) ;

    double price = sum_c_max * exp (-r*time) / no_paths;

Could anyone help me?

MAX

What *exactly* are you doing trying to reduce the output of rand()
modulo RAND_MAX + 1?  Are you perhaps thinking that it might return
greater than RAND_MAX?  What do you think RAND_MAX means?

More intriguingly, what happens when RAND_MAX == INT_MAX? ;-)

I've no idea where prices is declared, or where S_t, R and SD are
initialized.

Is that `r' meant to be the same as the previous `R'?  Are you sure you
want to use the name `time'?

Maybe you want to reinitialize S_t here.

Nope.  That's not C.  Definitely not.

Nor's that.

I doubt it.

-- [mdw]