hdu2206IP的计算

#include<iostream>
#include<cstring>
#include<cstdio>
#include<cmath>

using namespace std;

char s[11000];

int main()
{
    while(gets(s))
    {
        int l = strlen(s),i,j,k;
        bool bl = 1;
        for(i = 0;i<l;i++)
            if(!((s[i]>=‘0‘&&s[i]<=‘9‘)||s[i] == ‘.‘)) bl = 0;
        int num = 0;
        for(i = 0;i<l;i++)
            if(s[i] == ‘.‘) num++;
        if(num!=3) bl = 0;
        num = 0;
        int a;
        for(i = 0;i<l;i++)
        {
            a = 0;
            bool b = 0;
            while(s[i]>=‘0‘&&s[i]<=‘9‘)
            {
                b = 1;
                a = a*10+s[i++]-‘0‘;
                if(a>1000) bl = 0;
            }
            if(a>255) bl = 0;
            if(b) num++;
        }
        if(num!=4) bl = 0;
        if(bl) cout<<"YES"<<endl;
        else cout<<"NO"<<endl;
    }
    return 0;
}