字符串中找出连续最长的数字串

#include
#include<string>
using namespace std;

int main()
{

    string str;
    str.resize(255);
    scanf("%s",&str[0]);
    //cin>>str;
    if(str.length()>255)
        perror("length");

    string tmp;//用来临时存放数字字符串
    string max;//存放最长的数字字符串
    int maxlength=0;

    for(int i=0;isize();i++)
    {
        //if(str[i]>'0'&&str[i]<'9')
         while(str[i]>='0'&& str[i]<='9')
         {
             tmp+=str[i++];
         }
        if(tmp.size()>maxlength)
        {
            max=tmp;
            maxlength=tmp.size();
        }
        tmp.clear();
    }

    printf("%s\n",max.c_str());
    //cout<
    return 0;
}