Big Number(hdu1018,大数的位数log)

题意：N！的位数

思路：log10的使用，log10(1*2*3*4........*n) = log10(1) + log10(2)+.............

#include<iostream>
#include<cstring>
#include<cstdio>
#include<cmath>
using namespace std;

int main()
{
    int t;
    scanf("%d",&t);
    while(t--)
    {
        int n = 0;
        double sum = 0;
        scanf("%d",&n);
        for(int i = 1;i <= n; i++)
        {
            sum = sum + log10(i);
        }
        printf("%.0lf\n",sum+0.5);
    }
    return 0;
}