is it possible to make function that will accept multiple data types for given argument?

Question

Writing a function I must declare input and output data types like this:

int my_function (int argument) {} 

Is it possible to make such a declaration that my function would accept variable of type int, bool or char, and can output these data types ?

//non working example [int bool char] my_function ([int bool char] argument) {} 

Answer 1

Your choices are

ALTERNATIVE 1

You can use templates

template <typename T>  T myfunction( T t ) {     return t + t; } 

ALTERNATIVE 2

Plain function overloading

bool myfunction(bool b ) { }  int myfunction(int i ) { } 

You provide a different function for each type of each argument you expect. You can mix it Alternative 1. The compiler will the right one for you.

ALTERNATIVE 3

You can use union

union myunion {      int i;     char c;     bool b; };  myunion my_function( myunion u )  { } 

ALTERNATIVE 4

You can use polymorphism. Might be an overkill for int , char , bool but useful for more complex class types.

class BaseType { public:     virtual BaseType*  myfunction() = 0;     virtual ~BaseType() {} };  class IntType : public BaseType {     int X;     BaseType*  myfunction(); };  class BoolType  : public BaseType {     bool b;     BaseType*  myfunction(); };  class CharType : public BaseType {     char c;     BaseType*  myfunction(); };  BaseType*  myfunction(BaseType* b) {     //will do the right thing based on the type of b     return b->myfunction(); }