Cattle brush off network problems are summarized -Day3

1.C ++ in the cast

　　

    reinpreter_cast // <-ID type> (expression The)
    // type-ID must be a pointer, reference, arithmetic type, function pointer or a pointer member
    S SS;
    S & SS = PS *;
    int = A reinterpret_cast <int> (PS) ; // reinterpret_cast simply copied to bits ps a
    COUT a << << "" << endl << ps; // 7208636 0x6dfebc

    // const_cast <type_id> (expression) - type_id -> a pointer or reference
    // same type_id and type of expression - modify the object const / volatile - forcibly canceled object const
    const int CI = 10;
    int & BI = const_cast <int &> (CI);
    COUT BI << << "" << endl << CI; 10 // 10
    COUT BI & << << "" << endl << & CI; // address 0x6dfeb4 0x6dfeb4 same two variable
    bi = 8;
    << << BI COUT "" << endl << CI; 10. 8 //
    COUT BI & << << "" << endl << & CI; 0x6dfeb4 0x6dfeb4 //
    // may be used when the function parameter passing

    // static_cast <type-id> ( expression) - corresponds most explicit or implicit conversion
    // This expression is converted to the operator type-id type, but without run-time type checking to ensure the security of the converted

   
    // dynamic_cast only for pointers and references to objects, mainly used for the implementation of "safe downcast."

 

 Also on the volatile:

　　　　　volatile similar to the well known const is a type modifier

　　　　volatile is to instruct the compiler to illustrate it modifies the object to perform optimization should not be - the role of volatile is used for multi-threaded programming

 

2. row pointer declaration

　　int a[5][10];

　　int (* p) [10] = a; points to a number of elements in each row pointer 10

 

3. Several file manipulation functions

　　int fseek( FILE* stream, long offset, int fromwhere );　　

　　fseek to position the file pointer to the relocation fromwhere position (0 SEEK_SET file header, the current position of the file SEEK_CUR 1, SEEK_END end of the file 2) start offset byte offset; return 0 on success, -1 failure;

　　

　　long ftell(FILE* stream);

　　Returns the current file pointer position offset position with respect to the number of bytes of the file header;

　　

　　

4. How to convert binary tree forest

　　

　　First a tree into a binary tree basic principle is: the left child of its true children, their brothers and their children the right

　　

　　Forest converted to a binary tree:

　　　　　　　　　　　　　　First tree forest is converted into a binary tree Yi Keke

　　　　　　　　　　　　　　Do not move from a binary tree, binary tree after the root node as the root node of a binary tree in front of the right child

　　　　　　　　　　　　　　All the trees to turn into the binary tree

　

 

It can be seen: F converted into a corresponding binary tree forest T, the number of middle nodes is equal to F (T empty left child node number)

　　　　　Because children left their real children, converted to a binary tree in the forest leaf nodes in its left child must be empty

 

 

5. When a class object virtual function is called, C ++ uses - static binding

 

　　Static binding virtual function is called by the name of the object, at compile time can determine which virtual function call is a class

　　

　　动态联编 通过基类指针调用，在编译阶段无法通过语句本身来确定调用哪一个类的虚函数，只有在运行时指向一个对象后，才能确定调用时哪个类的虚函数