Difference between “::” “.” and “->” in c++

• - > for accessing object member variables and methods via pointer to object

Foo *foo = new Foo();
foo->member_var = 10;
foo->member_func();

• . for accessing object member variables and methods via object instance

Foo foo;
foo.member_var = 10;
foo.member_func();

• :: for accessing static variables and methods of a class/struct or namespace. It can also be used to access variables and functions from another scope (actually class, struct, namespace are scopes in that case)

int some_val = Foo::static_var;
Foo::static_method();
int max_int = std::numeric_limits<int>::max();