Big Number
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 32913 Accepted Submission(s): 15481
Problem Description
In many applications very large integers numbers are required. Some of these applications are using keys for secure transmission of data, encryption, etc. In this problem you are given a number, you have to determine the number of digits in the factorial of the number.
Input
Input consists of several lines of integer numbers. The first line contains an integer n, which is the number of cases to be tested, followed by n lines, one integer 1 ≤ n ≤ 107 on each line.
Output
The output contains the number of digits in the factorial of the integers appearing in the input.
Sample Input
2
10
20
Sample Output
7
19
这个题的意思是：给你一个数，让你求出N！由多少位数构成，比如输出10，它的阶乖是3628800 由7位数构成，这时你要输出7；
如果真的求阶乘，将是一个非常大的 数字，这里用对数来求位数。以下是详细代码：
#include<iostream>
#include <cmath>
using namespace std;
int main()
{
int N=0;
cin>>N;
while(N--)
{
int m=0;
cin>>m;
double number=0;//注意不能是int类型
for(int i=m;i>0;i--)
{
number+=log10(i);
}
cout<<(int)(number+1)<<endl;
}
return 0;
}