Visual C++ :: Dice Game - Creating Pass By Value Function Reference

i have a project where i create a dice game, the user rolls 2 dice and the computer roles 2 dice. the player that wins 3 out of 5 rolls wins the game. I have completed the requirements, but i wanted to create a pass by value function for "void Dice()", I'm not too sure how that works?

Code:

#include <iostream>
#include <ctime>
#include <cstdlib>
using namespace std;
//creating my variables and their values
int compinput;

[Code] .....