[C + +] The difference between "arrow" and "dot (.)"

Transferred from: http://blog.csdn.net/gyymen/article/details/4962873

First introduce the structure in C + +. For a structure:

struct mystruct{    int member_a;};

If you have a variable mystruct s, you can use the member elements in the following:

S.member_a = 1;  

If you use pointer method access, such as MyStruct * PS, then the same access must use the following form:

(*ps). member_a = 1;  

Or

When defining a class object as a pointer object, C + + uses a pointer to a member of the class, which needs to be used when defining a generic object. Points to a member in a class.
For example:

Class A{public    Play ();}

If defined as follows:
A *p is used: P->play (); The left is the structure pointer.
A p is used: P.paly (); On the left is the structure variable.

Summarize:
Arrow (): The left must be a pointer;
Point number (.): The left must be an entity.

[C + +] The difference between "arrow" and "dot (.)"