How can I achieve pass-by-reference in Pike?

anyone who can help and is familiar with the Pike language.

I am currently studying the Pike language and I would like to implement a void function that calculates the factorial of a given number "N". The "factorial" function should accept two parameters: the "N" parameter, which represents the calculation limit, and the "RESPONSE" parameter, which will store the calculated factorial value to be returned to the calling program.

I have searched extensively, but I couldn't find any information regarding passing parameters by reference in Pike. It seems like a rather obscure topic or perhaps not widely discussed. I have attempted various parameter passing techniques such as using "*", "&", "ref", "object", "array[][" but unfortunately, none of them worked. I even tried to simulate the pass-by-reference style used in the TCL language, but it also failed to produce the desired result.

If anyone has any insights or suggestions on how to achieve pass-by-reference behavior in Pike, I would greatly appreciate your assistance.

void factorial (int N, ref int FAT) {
  for (int I = 1; I <= N; I++) {
    FAT *= I;
  }
}

Pike doesn't have pass-by-reference, but it does have certain reference types that are always implicitly handled via pointers. For example, if a method takes an array parameter, then it actually has a pointer to the same array as the code that calls it, and if it mutates any elements of that shared array, the result will be visible to that calling code. So you can use a single-element array as a sort of de facto pointer, like this:

void fatorial(int N, array(int) FAT) {
    FAT[0] = 1;
    for (int I = 1; I <= N; I++) {
        FAT[0] *= I;
    }
}

int main() {
    array(int) RESP = allocate(1);
    
    RESP[0] = 1;

    factorial(5, RESP);
    write("Factorial = " + RESP[0] + "\n");

    return 0;
}