Java Class .vs. a C/C++ struct

Java Class .vs. a C/C++ struct


	In its simplest form a class is just a struct. For example, the simple class

          class Point{

              public int x,
                         y;
          }

is nothing more than the C/C++ struct

          struct Point{

              int x,
                  y;
          };


	There is a small but important difference in their use in C/C++ and Java, however. In both cases they are templates that are used to declare variables of a new type. But the C/C++ declaration

          Point p;
          p.x = 3;
          p.y = 5;

allocates an actual struct in memory to which values can be assigned to the various components, whereas the Java declaration

          Point p;
          p = new Point();
          p.x = 3;
          p.y = 5;

of the Point p just allocates storage for a pointer (called a reference) to a struct. The statement
p = new Point(); must be used to allocate and initialize the struct that actually represents the point.