Abusing C++ exceptions

Java and C# programmers use exceptions all over the place in their programs. C++ programmers have always been rather shy when it comes to exceptions. I’m not a particularly big fan of exceptions, but I find them helpful in getting me out of recursion trees!

The following snippet shows a typical recursive function that aims to find a target value by brute force. I’ve left out the details in order to highlight the most important feature : breaking out of the recursion tree once the value is found.

void go(int i)
{
   if(i == n)
   {
      // Perform calculation
     
      if (resultFound)
      {
         // This breaks out of the entire recursion 
         // tree and goes back to main!
         throw 1;
      }
   }
   else
   {
      state[i] = value1;
      go(i+1);
      state[i] = value2;
      go(i+1);
   }
}

int main()
{
   try {
      go(0);
   } catch(...) {}

   return 0;
}

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