fzu Problem 1396 Large Caclulating Work

#include <cstdio>
#include <iostream>
#include <cmath>
#include <algorithm>
#include <cstring>
using namespace std;
long long gcd(long long a,long long b)
{
if(b==0)
return a;
return gcd(b,a%b);
}
int main()
{
int t;
int cas=0;
while(scanf("%d",&t),t)
{
int n,ans;
scanf("%d",&n);
ans=n;
for(int i=2;i<=t;i++)
{
scanf("%d",&n);
ans=gcd(ans,n);
}
printf("Test Data %d:\n",++cas);
printf("%d\n",ans);
}
return 0;
}