Course paper + code and executable EXE file of library information management system based on C language

Catalog
One 、 Purpose and requirements of the experiment 0
Two 、 Overview of algorithm principle 0

1. In order to find 1
2. Two points search 1
3. Tree table search 3
4. Hash lookup 4
   3、 ... and 、 Software development environment and tools 11
   Four 、 Experimental content 11
   5、 ... and 、 Summary of the experiment 25
   6、 ... and 、 reference ： 26

5. else   37
   

6. else   38
   

7. else   39
   

8. else   39
   

9.     else   40
   

10. else   40
    

11.     else   46
    

12.     else   50
    

One 、 Purpose and requirements of the experiment
（1） Representation and implementation of set structure .
（2） Implementation of search and sorting algorithm .
（3） File access operation
（4） system function ： Book collection and editing 、 Book Search 、 Functions such as book circulation and personal information
（5） The program can check the fault tolerance of input data , Guarantee the validity of data .
（6） User interface friendliness ： The program can provide menus for users to choose and corresponding interactive information .
Two 、 Overview of algorithm principle
( One ) lookup
1. Search algorithm categories ：
（1） Static search and dynamic search ;
Both static and dynamic are for lookup tables .
Dynamic table refers to the table with delete and insert operations in the lookup table .
（2） Unordered search and ordered search .
Unordered search ： The sequence to be searched is in order and disorder ;
Search in order ： The searched sequence must be an ordered sequence .
2. The basic concept of search
（1） lookup : In the data set , The process of finding data elements that meet certain conditions is called finding .
（2） Lookup table （ Find structure ）; The set of data used for lookup is called a lookup table .
（3） A keyword is the value of a data item in a data element , It can be used to identify a data element , If this keyword can uniquely identify a record , Keywords used as primary keywords .
（4） The average search length is the average number of keyword comparisons in all search processes .
about n A table of elements , Given value key Same as... In the table i The elements are equal , To be carried out n-i+1 Sub keyword comparison .
Average search length （Average Search Length,ASL）： Need and specify key Expected number of keywords to compare , It is called the average search length when the search algorithm is successful .
For containing n Look up table of data elements , The average length of successful search is ：ASL = Pi*Ci And .
Pi： Look up the... In the table i Probability of data elements .
Ci： Find No i The number of times that data elements have been compared .
3、 Common search algorithms

1. In order to find
   Premise ： Sequential search is suitable for linear tables whose storage structure is sequential storage or linked storage .
   The basic idea ： Sequential search is also called linear search , It belongs to the unordered search algorithm . Start at one end of the data structure linear table , Sequential scanning , Scan the node keyword and the given value in turn k Comparison , If equal, the search is successful ; If no keyword is found at the end of the scan k The node of , Indicates that the search failed .
   Complexity analysis ：
   The average search length when the search is successful is ：（ Suppose that the probability of each data element is equal ） ASL = 1/n(1+2+3+…+n) = (n+1)/2 ;
   When the search fails , need n+1 Compare it to , The time complexity is O(n);
   therefore , The time complexity of sequential lookup is O(n).