1. {} is more powerful than () and thus is preferred over (). You should use always use {} except for a few cases where () is necessary. For example, if you want to create a vector of length 1000, you have to use

   vector<int>(1000);
   

instead of

    vector<int> {1000};

which create a vector with one element 1000.

1. Objects in C++ are intialized to have some value when they are created, i.e., an object in C++ always have a valid value. This is different from Java. In Java, objects are essentially references. If an object in Java does not point to any memory when initializing, it is null. In C++, it is impossible to have null object. You can only have null pointers in C++.

2. Universal initialization list {} is very powerful and convenient, especially when working with containers. However you cannot initialize non-const reference using {} using g++ 4.7, which seems to be a bug.