Example

#include <typeinfo>

class Shape{
public:
virtual ~Shape()=0;
};

class Circle : public Shape{};
class Square : public Shape{};

void function(const Shape * s)
{
if (typeid(*s)==typeid(Circle))
{
//do something for Circle
}
else if (typeid(*s)==typeid(Square))
{
//do something for Square
}
}

Solution

Implement the classes using virtual classOf() functions that return unique identifiers, or test the success of a dynamic cast.

class Shape{
public:
virtual ~Shape()=0;
};

class Circle : public Shape{};
class Square : public Shape{};

void function(const Shape * s)
{
Shape *sh = const_cast<Shape*> (s);

if (dynamic_cast<Circle *>(sh) )
{
//do something for Circle
}
else if (dynamic_cast<Square *>(sh) )
{
//do something for Square
}
}