[Template] - Large prime number determination

#include<bits/stdc++.h>
using namespace std;
long long quick_mod(long long a,long long b,int m)
{
    long long ans = 1;
    while(b!=0)
    {
        if(b&1)
            years = (years * y)%m;
        a = (a*a)%m;
        b /= 2;
    }
    return ans;
}
bool rqui_prime(int x)//x cannot exceed int /// shizhushuyes = true
{
    srand(time(0));
    int n = log(x)+7;
    if(quick_mod(7,x-1,x) != 1)
    {
        return false;
    }
    for(int i = 0; i < n; i++)
    {
        long long k = rand()%10000+7;
        if((k%x)&&(quick_mod(k,x-1,x)!=1))
        {
            return false;
        }
    }
    return true;
}