请大神看看，哪里错了

#include<bits/stdc++.h>
long long stk[1001],slen=0,tmp=0;
char s[1001];
int main()
{
    gets(s);
    int len=strlen(s);
    for(int i=0;i<=len;i++)
    {
        if(s[i]=='@') break;
        if(s[i]<='9'&&s[i]>='0')
        {
            tmp=tmp*10+s[i]-'0';
        }
        else if(s[i]=='.')
        {
            int res;
            if(s[i]=='+') res=stk[slen+stk[slen-1]];
            else if(s[i]=='-') res=stk[slen-1]-stk[slen];
            slen=slen-2;
            slen++;
            stk[slen]=res;
        }
    }    
    printf("%d\n",stk[slen]);
    return 0;
}