Digit of factorial

#include<bits/stdc++.h>


using namespace std;
#define ll long long

int main()
{
//    freopen("in.txt","r", stdin);
//
//    freopen("out.txt","w", stdout);

    vector<double> v ;
    v.push_back(0);

    for(ll i = 1 ; i <= 1000000 ; i++)
    {
        double s ;
        s = log10(i);
        v.push_back(s + v[i-1]);
    }

    ll T, t = 0;
    scanf("%lld",&T);

    while (T--)
    {
        ll n, b;
        scanf("%lld %lld",&n, &b);

        double d=0 ;

        ll ans;

        if (n == 0)
        {
            ans = 1;
        }
        else
        {
            ans = (v[n] / log10(b)) * 1.0 ;
            ans++;
        }

        printf("Case %lld: %lld\n",t+1,ans);

        t++;
    }
    return 0 ;
}