Question

What is the best way to have an associative array with arbitrary value types for each key in C++?

Currently my plan is to create a ‘value’ class with member variables of the types I will be expecting. For example:

class Value {      int iValue;     Value(int v) { iValue = v; }      std::string sValue;     Value(std::string v) { sValue = v; }      SomeClass *cValue;     Value(SomeClass *v) { cValue = c; }  };  std::map<std::string, Value> table; 

A downside with this is you have to know the type when accessing the ‘Value’. i.e.:

table['something'] = Value(5); SomeClass *s = table['something'].cValue;  // broken pointer 

Also the more types that are put in Value, the more bloated the array will be.

Any better suggestions?

Answer 1

boost::variant seems exactly what you are looking for.