篩選出對稱字符串，然后將其排序。

輸入樣例：

123321

123454321

123

321

sdfsdfd

121212

\\dd\\

輸出樣例

123321

\\dd\\

123454321

#include<fstream>
#include<iostream>
#include<string> 
#include<set> 
using namespace std;bool isSymmetry(string);//判斷字符串是否為對稱struct strComp{//將字符串用set進行排序bool operator()(const string &s1, const string &s2){if (s1.length() != s2.length())return s1.length() < s2.length();elsereturn s1 < s2;}
};int main(){ifstream cin("data.txt");string str;set<string, strComp> strSet;while(cin >> str){if (isSymmetry(str))strSet.insert(str);}for(set<string, strComp>::iterator it = strSet.begin(); it != strSet.end(); ++it)cout << *it << endl; return 0;
} bool isSymmetry(string str){int i = 0;int j = str.length() - 1;bool flag = true;while(i <= j){if (str[i++] != str[j--]){flag = false;break;}}return flag;
}