C++ variable initialization is quite complex, with several distinct categories that differ in behavior. The following list attempts to make sense of it. Default initialization Default initialization applies when no initializer is specified at all, or when a class member is omitted from the member initialization list. Primitive types remain uninitialized! T t; new T; Value initialization Initialization to a default value. For class-types, this is essentially identical to default initialization, but primitive types are zero-initialized. T t{}; T(); T{}; new T(); new T{}; : member(), member{} // class member initializer lists Direct initialization Direct initialization applies when initializing objects without explicit assignment. It also is also used for explicit casts, whether function-style or via static_cast and applies to Lambda closure arguments captured by value (which may be regarded as a special case of member initialization). During direct initialization, both explicit and non-explicit constructors are…