Abstracting the amount of rolls a die can do in c++

New to C++ and I am trying to make a die mechanic in my game. I am trying to see if i can do what i did for the sides of the die(a) being able to make it as many sides as needed. Now i need to do the same with how many times the dice gets rolled. If there is a better way i would also like to see it.

#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;

int rDice(int a);

int main()
{
  int z;
  z = rDice(20);
  cout << "The result is " << z;    

}

// takes a value of sided dice (a) and returns the value through d int rDice(int a)

 {

    srand(time(0));
    int d;
    d = 1+(rand()%a);
    return d; 
}