using 'auto' in std::map

Question

I'm parsing a JSON file, the values can consist of integer, string or float. Normally I have a map defined like this:

 std::map<std::string, std::string> myMap;

The problem is I'm not clear how to use map if there can be different data types, I tried:

 std::map<std::string, auto> myMap;

but I get an error:

'auto' is not allowed here

Is there I way I can use it with different data types or do I need to define an object, which can contain different data types, for example:

Class MyObject
{
  private:
    int integerValue;
    std::string stringValue;

  public:
    void setValue( std::string value, int type );
}

MyObject::setValue( std::string value, int type )
{
    if( type == 0 )
       stringValue = value;
    else if( type == 1 )
       integerValue = stoi( value );
}

Or is there a better way to do this? Thanks!

Answer 1

In order to achieve what you ask, use:

std::map<std::string, std::any> myMap;

For example:

#include <map>
#include <string>
#include <any> // Since C++17

main()
{
    std::map<std::string, std::any> myMap;

    std::string strName{ "Darth Vader" };
    int nYear = 1977;

    myMap["Name"] = strName;
    myMap["Year"] = nYear;

    std::string strS = std::any_cast<std::string>(myMap["Name"]); // = "Darth Vader"
    int nI = std::any_cast<int>(myMap["Year"]); // = 1977
}