Why is it a bad idea to use 'new'? [duplicate]

Answer 1

It depends on what the code needs. It the reply you refer to, the vector contains client instances, not pointers to client instances.

In C++, you can create object directly on the stack, without using new, like V1 and V2 in the code below:

void someFct()
{
     std::vector V1;
     //....
     std::vector V2;
}

When using V2, you will have to create new client instance with the new operation, but the client objects will not be released (deleted) when V2 will go out of scope. There is no garbage collector. You have to delete the objects before leaving the function.

To have the created instances deleted automatically, you can use std::shared_ptr. That make the code a bit longer to write, but it is simpler to maintain in the long term:

void someFct()
{
    typedef std::shared_ptr client_ptr;
    typedef std::vector client_array;
    client_array V2;

    V2.push_back(client_ptr(new client()));

    // The client instance are now automatically released when the function ends, 
    // even if an exception is thrown.
}