'std :: string'没有名为'front'的成员

Question

#include <string>
#include <algorithm>
#include <iostream>

int main()
{
    string str;
    string str1;
    int h = 0;
    cin >> str;
    if (str.length() > 10)
    {
        str1 += str.front();
        h = str.length() - 2;
        string s = to_string(h);
        str1 += s;
        str1 += str.back();
        cout << str1;
    }
    else cout << str;
    return 0;
}

编译在XCode中,但不在codeforces.ru/上

 ?an't compile program.cpp:
program.cpp: In function 'int main()':
program.cpp:23:21: error: 'std::string' has no member named 'front'
program.cpp:27:29: error: 'to_string' was not declared in this scope
program.cpp:32:21: error: 'std::string' has no member named 'back'

Answer 1

一件事是,string::front和std::to_string因为C++ 11引入.您必须确保使用支持这些新功能的编译器.

Answer 2

string::front在c ++ 11中引入.在mac上确保你使用clang,因为g ++在osx上没有更新,并且使用命令行选项clang++ -std=c++11 your_program.cpp.您可能还需要使用该选项-stdlib=libc++