http://acm.hdu.edu.cn/showproblem.php?pid=5007

纯属联系String的substr

当substr截取的长度小于写的话

string te;
    int n;
    te="Hellow";
    cout << te.substr(3,5);

写的时候没去限制边界还是AC了

//#pragma comment(linker, "/STACK:102400000,102400000")
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <string>
#include <iostream>
#include <iomanip>
#include <cmath>
#include <map>
#include <set>
#include <queue>
using namespace std;

#define ls(rt) rt*2
#define rs(rt) rt*2+1
#define ll long long
#define ull unsigned long long
#define rep(i,s,e) for(int i=s;i<e;i++)
#define repe(i,s,e) for(int i=s;i<=e;i++)
#define CL(a,b) memset(a,b,sizeof(a))
#define IN(s) freopen(s,"r",stdin)
#define OUT(s) freopen(s,"w",stdout)
const ll ll_INF = ((ull)(-1))>>1;
const double EPS = 1e-8;
const double pi = acos(-1.0);
const int INF = 100000000;

int main()
{
    string s;
    while(cin>> s )
    {
        int len=s.size();
        for(int i=0;i<len;i++)
        {
            string s4=s.substr(i,4);
            string s5=s.substr(i,5);
            string s6=s.substr(i,6);
            if(s4 == "iPod" || s4 == "iPad" || s5 == "Apple" || s6=="iPhone")
                puts("MAI MAI MAI!");
            if(s4 == "Sony")
                puts("SONY DAFA IS GOOD!");
        }
    }
    return 0;
}

hdu 5007 水 字符串