ifelse Vs Map? [C++]

• I have a class that receives key and value parameters from other classes.
• Both key and value are std::string.
• Right now the function setParameter uses a chained if-else if -else if - else logic:

void setParamater(std::string key, std::string value){
    if(key == KEYPARAM_1)
    {
       //Do something
    }
    else if(key == KEYPARAM_2)
    {
       //Do something
    }
    else if (key == KEYPARAM_3)
    {
       //Do something
    }
    else if (key == KEYPARAM_4)
    {
        //Do something
    }
    else if (key == KEYPARAM_5)
    {
       //Do something
    }
    else if (key == KEYPARAM_6) {
       //Do something
    }
    else
    {
        //Do something
    }
}

• I find this very ugly and its a code that makes many unnecasary comparisons (the more parameters the more comparions).

• I had the idea of doing a map of string and functinos: std::map<std::string; std::funtion<std::string>> to replace this code.

• The first std::string would be the key, the std::functionwould replace the code in the //Do something lines and the other std::string would be the value.

• The negative part of this solution is that I would be creating an object for each key and I would have to find a nice place to declare all the functions. The good thing is that is easy to call and wont do all the ifelse comparisons. Somehing like this would be kind of pretty:

void setParamater(std::string key, std::string value){
      my_map(key, f(value)); //I'm not sure about the syntax in there
}

• Does someone have a better idea to replace the if-else chain? Is the map a good idea?

-FYI: each case does something quite different is not just a setters.

Thank you!