smart_yourself_exception.cpp

#include <sstream>
#include <string>

class AException {
public:
    AException(const std::string& whatsWrong) 
        : name( whatsWrong ),
          row(-1)  {}  
        
    AException(const std::string& whatsWrong, unsigned long int _row) 
        : name( whatsWrong ),
          row(_row) {}
        
    string what()const {
        std::stringstream errS;
        errS << name;
        if ( row > 0 ) { 
            errS << ". at line : " << row;
        }   
        return errS.str();
    }   
private:
    long int row;
    std::string name;
};