Digits of factorial !

#include <bits/stdc++.h>
#define maxn 1000001
#define ll long long
using namespace std;

double a[maxn];

void factorial( ){
    for(int i=1;i<=1000000;i++){
        a[i]=a[i-1]+log(i);
    }
}

int main()
{
    factorial();
    int t,n,b,cas=0;
    cin>>t;
    while(t--){
        scanf("%d%d",&n,&b);
        long long ans=(a[n]/log(b))+1;
        printf("Case %d: %lld\n",++cas,ans);
    }
}