There are usually two ways to check a phone number, one is to browse the phone book, and the other is to dial "114" (telephone number inquiry desk). Phone books are not available everywhere, and it is not so easy to search. However, if you dial "114", as long as you make a request, it will tell you the answer quickly and accurately, so the "114" information desk is becoming more and more popular among people. . Now, the Shanghai Inquiry Center handles an average of 180,000 inquiry calls every day. "114" has become one of the indispensable telecommunications services in modern civilized society. The early "114" relied on manual inquiries. Before a full-time enquiry officer takes up the job, he or she often has to memorize hundreds or thousands of frequently used telephone numbers, and also has to prepare many categorized cards around him in order to be able to look them up at any time. When you ask for a number she knows well, she tells you immediately, otherwise she has to look through the card and find it before answering. In this way, you often need to wait for some time when checking the number. Today's query business is basically completed by computers. Computers store much more information than phone books. When the enquirer receives your inquiry, she only needs to press a few keys on the computer, and the computer will quickly find the phone number you want and use a dedicated "simulator" to imitate a human voice. Number. In order for the computer to complete the query quickly and correctly, it is usually necessary to establish a "database" inside it, in which thousands of phone numbers are arranged and stored in an orderly manner according to certain rules, so that they can be queried at any time. There are many ways to arrange telephone numbers. For example, they can be divided by industry, including industry, agriculture, commerce, transportation, justice, culture and education, tourism, etc. Industry can be divided into heavy industry, light industry, etc., and light industry can be divided into textiles, daily household appliances, etc. etc. Daily household appliances can be divided into many different specialties such as washing machines and televisions. For another example, you can arrange all unit names in alphabetical order of pinyin. Of course, there are many ways to build a database and search, and the actual situation is much more complicated. However, due to the extremely fast computing speed of computers, hundreds of thousands or millions of times per second, no matter how complex this type of query is, it is just a piece of cake for the computer. It can be processed easily and can be processed in an instant. The answer is given with almost no waiting time for the inquirer.