From the cpp core guidelines: https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Res-nullptr **Reason** Readability. Minimize surprises: `nullptr` cannot be confused with an `int`. `nullptr` also has a well-specified (very restrictive) type, and thus works in more scenarios where type deduction might do the wrong thing on `NULL` or `0`. Consider: ```cpp void f(int); void f(char*); f(0); // call f(int) f(nullptr); // call f(char*) ```