Throw an exception for non-cofingurable number of vector elements...

[Homestead]

Here is my program

std::cout<<"Hey, Nina, tell me how many elements you want to use uhmm ?"<<std::endl;
std::cout<<"After you input the number, I will give you a vector "<<std::endl;
std::cin>>numElem;
std::vector<double> vec(numElem);
if(!vec){
throw std::cerr<<"Sorry, I cant do it for you, another try please"<<std::endl;
exit(1);
}
else 
std::cout<<"Cool, there you go, my lady"<<std::endl; 

Could you tell me if my exception thrown is correct in this case ? if not, how can I fix it ? May I have you fix it for me please ?

Thanks a lot,

Regards,
homestead

[Kheun]

See here for excepting throwing and handling.

[Paul McKenzie]

Originally posted by Homestead
Here is my program

std::cout<<"Hey, Nina, tell me how many elements you want to use uhmm ?"<<std::endl;
std::cout<<"After you input the number, I will give you a vector "<<std::endl;
std::cin>>numElem;
std::vector<double> vec(numElem);
if(!vec){

There is no such thing as a "NULL" vector, therefore your check is invalid. if an exception is thrown, it would have been thrown before it even hits the if() statement. Therefore, this code should be in a try/catch block.

exit(1);

You shouldn't call exit like this in a C++ program. You bypass the destructors of any objects.

Could you tell me if my exception thrown is correct in this case ? if not, how can I fix it ?

#include <iostream>
#include <vector>
#include <exception>

int main()
{
  int numElem;
   std::cout<<"Hey, Nina, tell me how many elements you want to use uhmm ?"<<std::endl; 
  std::cout<<"After you input the number, I will give you a  vector "<<std::endl; 
  std::cin>>numElem; 
  try {
    std::vector<double> vec(numElem);
    std::cout<<"Cool, there you go, my lady"<<std::endl;
  }
  catch(...)  // Most likely, this is bad_alloc
  {
     std::cout << "Something went wrong";
  }
}

Regards,

Paul McKenzie

[Homestead]

Thanks Kheun,
Thanks Paul alot,

Regards,

homestead