c++ - Visual Studio 2010 x64 中 map 的运行时错误

Question

我一直在尝试在 Visual Studio 2010 中创建一个示例应用程序。我没有发现问题所在，因为代码可以完美编译，但会出现运行时错误。这是代码:

#include <Map>
#include <string>
#include <sstream>
#include <iostream>
#include <fstream>

using namespace std;

int main(int argc, char* argv[])
{
    map <int, string> *sss = new map<int, string>;
    sss->at(0) = "Jan";
    sss->at(1) = "Feb";
    sss->at(2) = "Mar";
    sss->at(3) = "Apr";
    sss->at(4) = "May";
    sss->at(5) = "Jun";
    string current = NULL;
    ofstream myfile;
    myfile.open("daily_work.txt");
    myfile << "*****   DAILY WORK   *****" << endl;

    for(int i = 0; i < 6; i++)
    {
        string month = sss->at(i);
        for(int j = 1; j < 31; j++)
        {
            stringstream ss;
            ss << j;
            current = ss.str();
            current.append(" ");
            current.append(month);
            current.append(" = ");
            myfile << current << endl;
        }

        current = "";
    }

    printf("Completed!");
    myfile.close();
    sss->clear();
    delete sss;
    sss = NULL;
    return 0;
}

错误在 main 的第 2 行抛出。

sss->at(0) = "Jan";

请在此处查找错误:

Answer 1

来自 http://en.cppreference.com/w/cpp/container/map/at :

Returns a reference to the mapped value of the element with key equivalent to key.
If no  such element exists, an exception of type std::out_of_range is thrown.

你需要:

map <int, string> sss;
sss[ 0 ] = "Jan";