What are structured data storage types?

In C, there are two terms: data type and data storage class.

A data type is generally used to represent the number of bytes a variable occupies in memory.

For example, char ch = 'a'; A character variable ch is defined, initialized as character a, and the variable with data type char generally occupies one byte of memory space in memory, and its corresponding function is sizeof(), which can find the number of memory bytes occupied by a certain data type on a specific platform. Another example is the int data type, the size of the int data type, generally speaking, is the same as the size of the registers in the processor, for different platforms, 16 bits, 32 bits, 64 bits are possible, that is, 2 bytes, 4 bytes, 8 bytes, etc.

The above is the data type.

There are 4 types of storage classes: auto, static, extern, and register

auto is the default storage type, which means you declare a variable, such as int i; Equivalent to auto int i; Auto isn't much of a use for a programmer, it's a different story for a compiler designer.

static declares static data, which is the lifetime of a variable, and in layman's terms, how long it can function (if I'm not mistaken), This type of storage of variables coexists with your program, such as defining static int count = 10; Unless you change it, or the program exits, it's always there.

extern is a storage type, which is usually a declarative variable, or function, that tells the compiler that so-and-so is defined elsewhere, for example.

in source code

extern int p(unsigned i);

In another source file of this program, there is a definition of this function p, such as.

in source code

int p(unsigned i)

if(i>0)

return 1;

elsereturn 0;

The regiter storage class tells the compiler to try to put a variable in the register as much as possible, which is the programmer's concern for the speed of access to the variable, and there are not many chances to see such a declaration these days, because declaring register disrupts the compiler's own optimization strategy, but, again, some people are still doing this.

I hope what I've said above will help you, even a little bit.

Structured data storage is to store data according to a certain structure, such as nsdictionary for iOS, where a health corresponds to a value. In order to facilitate the operation of data, there are generally three types.

Key-value archiving (a key, corresponding to a value, the key takes the value).

A list of attributes (such as xml file storage).

Database storage (direct storage of databases).

The storage structure is:

(This set of storage units can be contiguous or discontinuous).

Example: Chains. Examples: arrays, chains.

Example: Clue tree.

4. Hashing. Storage: Scattered pure knowledge column storage, also known as hash storage, is a search technology that tries to establish a correspondence between the storage location of data elements and key codes.

Example: Stack (which can be stored sequentially or randomly).

In the sequential storage, each storage space contains the information of the stored elements themselves, and the logical relationship between the elements is the sequential storage of the linear table simply calculated by the array subscript position, if the subscript position of an element stored in the corresponding array is i, then its predecessor element in the corresponding array is the subscript position of i-1, and its successor element in the corresponding array is i+1.

In a chained storage structure, the storage nodes contain not only the information about the elements themselves, but also the information about the logical relationships between the elements.

In the sequential storage of data, since the storage location of each element can be calculated simply, the time to access the elements is the same.

In the linked storage of data, since the storage location of each element is saved in its precursor or successor node, it can only be accessed by the pointer when its precursor node or successor node is accessed, and the time of accessing any element is related to the position of the element node in the chain storage structure.

The storage structure of the data refers toData structures(the logical structure of data) in a computer, also known as the physical structure. There are two main types of data storage structures: sequential storage structure and chain storage structure.

The main advantage of a sequential storage structure is that it saves storage space, because the storage unit allocated to the data is all used to store the data of the nodes (regardless of the size of the array in the C C++ language), and the logical relationships between the nodes do not take up additional storage space.

When this method is adopted, random access to nodes can be realized, that is, each node corresponds to a sequence number, and the storage address of the node can be directly calculated from the sequence number. However, the main disadvantage of the sequential storage method is that it is not easy to modify, and a series of nodes may have to be moved when inserting and deleting nodes.

The chain storage structure is generally in the hard disk of the computer, and the files are stored in a chained manner. We know that multiple sectors.

Forming a cluster, a cluster is the basic unit of data stored by a computer.

A file is stored in multiple clusters that may not be spatially connected. This is chained storage.

But in order to be able to read the file, the computer writes the cluster number of the second part at the end of the first part of the file. At the end of the second part, a third part is written, and so on, and the last part is written with a **, indicating that this is the last part of the document. It is worth mentioning that the high cluster number is behind.

The 1234 shown in ** is actually cluster 3412) The cluster occupied by the file can be considered to be randomly assigned.

The structure in which the data is stored. There are two different ways to represent the relationship between data elements: sequential and non-sequential images, resulting in two different storage structures

Sequential and chained storage structures. The storage structure of data refers to the representation of the logical structure of data in a computer.

Classification of storage structures in terms of data structures:The sequential storage method is to store logically adjacent nodes in storage cells adjacent to physical locations, and the logical relationship between nodes is reflected by the adjacency relationship of storage cells, and the resulting storage representation is called sequential storage structure. Sequential storage structures are one of the most basic storage representations, usually implemented with the help of arrays in programming languages.

The link-store method does not require logically adjacent nodes to be physically adjacent to each other, and the logical relationship between nodes is represented by an additional pointer field. The resulting storage representation is called a chained storage structure, which is usually implemented with the help of pointer types in a programming language.

b Representation of the logical structure of the data in a computer.

The storage structure of the data can be set structure, linear structure, tree structure and graph structure, as follows:

1) Collection: There is no relationship between the elements in the data structure except for the mutual relationship of "belonging to the same set";

2) Linear structure: The elements in the data structure have a one-to-one interrelationship;

3) Tree structure: The elements in the data structure have a one-to-many interrelationship;

4) Graph structure: There are many-to-many interrelationships between elements in a data structure.

Common Operations:1) Search. Retrieval is to find nodes in a data structure that meet certain conditions. Generally, given the value of a certain field, find the node with the value of the field.

2) Insert. Add a new node to the data structure.

3) Delete. Removes the specified node from the data structure.

4) Update. Change the value of one or more fields of a specified node.

5) Sorting. Rearrange the nodes in a specified order. For example, increment or decrement.

The above content Chang brother sedan reference: Encyclopedia - data structure.

1. Set structure: The data elements in the structure have no other relationship with each other except that they belong to the same type.

2. Linear structure: There is a one-to-one relationship between the data elements in the structure.

3. Tree structure: There is a one-to-many relationship between the data elements in the structure.

4. Graphical structure or network structure: There is a many-to-many relationship between the data elements in the structure.