an error handling code doubt

[rickenjus]

I want this code to call generic catch block whenever any special character(eg. !,@,#,$,%,&,*, etc) is entered in numerator or denominator. So what code should I add to this.
Any help would be appreciated. Thanks.

#include <iostream>
 
using namespace std;
 
int main()
{
    try                                                // generic catch block
    {  
       int num, den;
       double division;
       try
       {
         cout << "\n enter numerator(+ve no. only): ";
         cin >> num ;
         if (num<0) throw 3.2 ;
       }    
 
       catch(double m)
       {
          cout << "\n ERROR: numerator should be positive ";
          num = -num ;
          cout << "\n\n So your new numerator is: " << num;
       }         
 
       try
       {
          cout << "\n\n enter denominator: ";
          cin >> den ;
          if (den==0) throw 1;
       }
 
       catch(int n)
       {
          cout << "\n ERROR: You cannot divide a no. by zero, enter another no: ";
          cin >> den;
       }
 
       division = double(num)/den;
       cout << "\n result is: " << division << "\n\n ";
    }
 
    catch(...)                              // Generic catch block
    {
       cout << "/n/n Unexpected Error: Contact your software provider";
    }  
    system("PAUSE");
    return EXIT_SUCCESS;
}
 

[weaknessforcats]

I suggest you write a function that tests you input for the undesrired values and, if found, does a throw of an exception object.
which to catch as an exception&. Try to use the catch(...) as a last resort. Unknown exception types flyung around a C++ program is not a good idea.

For example, if the input is less than zero, throw an out_of_range exception. Your what method() can explain what the probem is. Do this rather than catching a double.

Just derive your exception class from std::exception and implement the what() method.