Memcpy leading to block freed twice error

I have a map which I am filling as needed. To get the contents of the map out into another variable I am using memcpy.

If the memcpy line is commented, I see the output print correctly displayed. 100 => 1234 Fruits

If I uncomment the memcpy, I see the below error. The previously seen print does not get displayed as well.

block freed twice

Exited: ExitFailure 127

#include <iostream>
#include <map>
#include <string>

struct apple
{
    int iValue;
    std::string str1;
};

typedef std::map<int, apple> AppleMap;

int main()
{
    AppleMap one;
    apple structaa;
    structaa.iValue = 1234;
    structaa.str1 = "Fruits";
    int value = 100;
    one[value]=structaa;

    AppleMap::iterator it = one.find(100);
    if(it != one.end())
    {
        std::cout << it->first << " => " << it->second.iValue << '\t' << it->second.str1 << '\n';
    }
    else
    {
        std::cout << "Value Not Found\n";
    }

    apple structbb; 
    memcpy(&structbb, &(it->second), sizeof(apple));

    return 0;
}

Any help on what I have done wrong?