C++ call function with string as parameter

Question

Lets say I have several functions like function1() , function2() , ....., function1000() and I am getting a string in a function lets say call_function(string function_name) .
Now I need to execute function based on function_name .

I searched for solutions and found I can use maps.

Is there any easy way to create a map for lets say 1000 keys(string type) and respective functions ?
eg: call_function(function541) then it should execute function541() ;

Answer 1

You can use map to function pointers for this stuff

void func1(const char *args)
{
     //....
}

void func2(const char *args)
{
     //....
}

typedef void (*function) (const char *args);

//......

std::map<std::string, function> func_map;

func_map.insert(std::pair<std::string, function>("func1", func1));
func_map.insert(std::pair<std::string, function>("func2", func2));

func_map["func1"]("arg1 arg2 arg3"); // Here is the func1 call

Answer 2

Is there any easy way to create a map for lets say 1000 keys(string type) and respective functions ?

eg: call_function(function541) then it should execute function541() ;

No, there is no easy way, because C++ does not have reflection . Function names only exist for the compiler. At run-time, there is no relationship between a function called function541 in your source code and the string "function541" existing in memory while the program is being executed.

Each and any of such links must be established manually:

std::map<std::string, std::function<void()>> map;
// ...
map["function541"] = function541;

Of course, you can still automate such a task with code generation. Functions with mechanical names like this don't look like manually written C++ code anyway. That is, you can write a script in some other language that creates the C++ code to add the thousand functions to the map, perhaps as some kind of pre-build step.

Still, from a run-time point of view, there's no automation whatsoever.