在红题前倒下了，大佬们扶扶我

#include<cstdio>
#include<cstring>
using namespace std;
int a[1100],len=0,x=0;
char st[1100];
int main()
{
	while(1)
	{
		scanf("%s",st+1);
		if(st[1]=='0')return 0;
		len=strlen(st+1);
		for(int i=1;i<=len;i++)a[i]=st[i]-'0';
		for(int i=1;i<=len;i++)x=(x*10+a[i])%11;
		if(x==0)printf("%s is a multiple of 11.\n");
		else printf("%s is not a multiple of 11.\n");
	}
}