Catching an exception class within a template
- by Todd Bauer
I'm having a problem using the exception class Overflow() for a Stack template I'm creating. If I define the class regularly there is no problem. If I define the class as a template, I cannot make my call to catch() work properly. I have a feeling it's simply syntax, but I can't figure it out for the life of me.
#include<iostream>
#include<exception>
using namespace std;
template <class T>
class Stack
{
private:
T *stackArray;
int size;
int top;
public:
Stack(int size) { this->size = size; stackArray = new T[size]; top = 0; }
~Stack() { delete[] stackArray; }
void push(T value)
{
if (isFull())
throw Overflow();
stackArray[top] = value;
top++;
}
bool isFull()
{
if (top == size)
return true;
else
return false;
}
class Overflow {};
};
int main()
{
try
{
Stack<double> Stack(5);
Stack.push( 5.0);
Stack.push(10.1);
Stack.push(15.2);
Stack.push(20.3);
Stack.push(25.4);
Stack.push(30.5);
}
catch (Stack::Overflow)
{
cout << "ERROR! The stack is full.\n";
}
return 0;
}
The problem is in the catch (Stack::Overflow) statement. As I said, if the class is not a template, this works just fine. However, once I define it as a template, this ceases to work. I've tried all sorts of syntaxes, but I always get one of two sets of error messages from the compiler.
If I use catch(Stack::Overflow):
ch18pr01.cpp(89) : error C2955: 'Stack' : use of
class template requires template argument list ch18pr01.cpp(13) : see
declaration of 'Stack' ch18pr01.cpp(89) : error C2955: 'Stack' : use
of class template requires template argument list ch18pr01.cpp(13) :
see declaration of 'Stack' ch18pr01.cpp(89) : error C2316:
'Stack::Overflow' : cannot be caught as the destructor and/or copy
constructor are inaccessible
EDIT: I meant
If I use catch(Stack<double>::Overflow) or any variety thereof:
ch18pr01.cpp(89) : error C2061: syntax error : identifier 'Stack'
ch18pr01.cpp(89) : error C2310: catch handlers must specify one type
ch18pr01.cpp(95) : error C2317: 'try' block starting on line '75' has no catch handlers
I simply can not figure this out. Does anyone have any idea?
