Blockchain smart contract tutorial

1. Do you want to learn blockchain development technology or just want to know what blockchain is? If it is the former, you can look at the code of other blockchain projects and learn about it first. If it is the latter, we can pay attention to some good blockchain we media. Blockchain is an emerging instry. There is no ready-made training course. It depends on self exploration and understanding.

2. Smart contract can be simply understood as a piece of code written on the blockchain, which is event driven, has dynamic state, obtains multi-party recognition, and can automatically process the information on the chain according to the preset conditions. Once an event triggers the terms in the contract, the code will be executed automatically. The biggest advantage of smart contract is to use program algorithm to replace human arbitration and contract execution
smart contract is a contract that uses computer language instead of legal language to record terms. Once it is written, it can be trusted by users. The terms of the contract cannot be changed, so the contract cannot be changed. If the procere meets the conditions, it will be carried out, and there is no human interference to ensure absolute fairness
three technical features of smart contract
● data transparency
all data on the blockchain are open and transparent, so the data processing of smart contract is also open and transparent, and any party can view its code and data at runtime
● can't tamper
all data of the blockchain itself can't be tampered, so the code of the smart contract deployed on the blockchain and the data generated by the operation can't be tampered, and the node running the smart contract doesn't have to worry about malicious modification of the code and data by other nodes
● permanent operation
the number of nodes supporting the blockchain network often reaches hundreds or even thousands. The failure of some nodes will not lead to the stop of the smart contract, and its reliability is close to permanent operation in theory, which ensures that the smart contract can be as effective as the paper contract at all times.

3. With the breakthrough of blockchain technology, the smart contract has a chance of rebirth. The smart contract based on blockchain technology can not only give play to the advantages of smart contract in cost efficiency, but also avoid the interference of malicious behavior on the normal execution of the contract. The smart contract is written into the blockchain in digital form, and the characteristics of blockchain technology ensure that the whole process of storage, reading and execution is transparent, traceable and unchangeable; At the same time, the strong security consensus mechanism does not need the intervention of three parties: a set of state machine system is constructed by the consensus algorithm of the blockchain, so that the intelligent contract can run efficiently.

4. Chongqing jinwowo analyzes the role of smart contract in blockchain technology as follows:
three characteristics of smart contract in blockchain can be summed up:
1) decentralization. It doesn't rely on the centralized server and runs automatically through the network nodes
2) good trust mechanism. The crisis of trust is greatly reced, and it is not necessary to consider whether the participation is trustworthy
3) high degree of autonomy. Once the condition is triggered, the contract will be executed automatically without interference

5. From a technical point of view, smart contracts are considered to be network servers, but these servers are not set up on the Internet using IP addresses, but on the blockchain (chain Nova). So that you can run specific contract programs on it. But unlike web servers, smart contracts can be seen by everyone, because the code and state of these smart contracts are on the blockchain (assuming that the blockchain is public). Moreover, unlike web servers, smart contracts do not rely on a specific hardware device. In fact, the code of smart contracts is executed by all devices involved in mining (this also means that the computing power to enter a single contract is limited, although the automatic adjustment of mining difficulty will adjust this effect). Smart contract is an assembly language programmed on blockchain. Usually people don't write stanza code by themselves, but they compile it from a higher-level language, such as solid, a special language similar to JavaScript. These bytecodes do provide guidance for the functionality of the blockchain, so the code can easily interact with it, such as transferring cryptography currency and recording events. The execution of the code is automatic: either it is successfully executed, or all state changes are revoked (including the information that has been sent or received from the current failed contract) This is very important because it avoids partial execution of the contract.

6. Chongqing jinwowo analyzes the principle of smart contract under blockchain technology as follows:
the principle of smart contract is the link between points, which exists in the physical and digital space, in the real world and the virtual world. It may exist in a certain space, or in two different spaces, which have natural links and are distributed, There is no centralization

7. Shanghai Heshu Software Co., Ltd. is a professional blockchain technology service provider in China. The smart contract seems to be a script that can be executed accurately. It can also be realized with traditional technology. Why must we use blockchain technology? Personal understanding of blockchain has two characteristics: 1. Data can not be modified or deleted, but can only be viewed and added; 2. Decentralization.

8. General banks can exchange, but limited to Monday to Friday, I suggest you can go to Bank of China and Bank of communications, especially Bank of China, this business is very perfect, you can also use RMB to exchange US dollars in the future.

9. 1. The four elements of monetary system are: the determination of monetary materials, the name of currency, monetary unit and price standard, the standard currency and subsidiary currency and their solvency, and the issuance guarantee system
2. At present, countries all over the world generally use the strength of financial asset liquidity as the main basis for dividing monetary levels< The forms of consumer credit include deferred payment, installment payment and consumer loan
4. Under the condition of coexistence of various interest rates, the decisive interest rate is the benchmark interest rate, which is usually the rediscount rate of the central bank in western countries
5. The operating principles of commercial banks are profitability, security and liquidity
6. The balance of autonomous transactions is usually used to judge whether a country's balance of payments is balanced
7. The central bank plays the role of lender of last resort on the premise of centralizing the deposit reserve of commercial banks
8. Investment financial institutions mainly include financial companies, mutual funds and money market mutual funds< According to Keynesian money demand theory, when the income level rises, the money demand of transaction motivation and prevention motivation will increase
1. The so-called "currency in circulation" is the sum of the currency that plays the function of means of circulation and the currency that plays the function of means of payment
2. Short term bonds issued by the state, acceptance bills issued by banks and large amount negotiable certificates of deposit can be realized in various forms such as transfer, discount and mortgage at any time in the money market, which can be transformed into real means of purchase and payment. We call them quasi currency
3. M1 in narrow sense is composed of cash and current deposit, while m2 in broad sense is composed of M1 and quasi currency
4. The creditor who provides commercial credit, in order to guarantee his claim to the debt, holds a kind of written credit certificate, which is called commercial paper
5. The way of issuing securities by the issuers themselves is direct issuance< In a narrow sense, off balance sheet business can be roughly divided into guarantee business, commitment business, loan sale and asset securitization
7. There are window guidance and moral advice in the indirect credit control of monetary policy tools
8. The central bank provides capital payment to commercial banks mainly through refinancing and rediscount< There are commercial banks, savings banks and credit cooperatives
10. According to the delivery time of foreign exchange transactions, the exchange rate can be divided into spot rate and forward rate
11. Since the birth of the monetary system, it has experienced four main forms of monetary system: silver standard system, gold and silver compound system, gold standard system and paper currency system
12. Paper money, bank notes, deposit money and electronic money are all credit money< The basic characteristics of credit are repayability and interest payment
14. Normally, nominal interest rate minus inflation rate can be regarded as real interest rate
15. As a special kind of enterprise, the business object of financial institutions is monetary capital and financial instruments< In 1994, in order to meet the needs of economic development, China established three policy banks, namely, China Development Bank, Export Import Bank of China and Agricultural Development Bank of China
17. In essence, the transaction object of financial market is monetary capital, which needs the help of monetary capital
18. The securities issuing market is also known as the primary market, which complements the securities circulation market and forms a unified securities market
19. The multiple of total deposit and original deposit is usually called deposit multiplier
20. In the balance of payments, when income is greater than expenditure, we call it surplus; On the contrary, when expenditure is greater than income, we call it deficit< Up to now, the basic structure of electronic computer is based on the idea of stored program, which was first developed by Feng; It was proposed by Neumann
22. The minimum configuration of microcomputer hardware includes host, keyboard and display
23. The start-up sequence of microcomputer should follow the sequence of peripherals before host< In microcomputers, the basic unit used to store information is byte
25. Floppy disk write protection prevents data from being modified
26. If 32x32 dot matrix Chinese characters are used, the storage capacity of 3755 dot matrix Chinese characters is 469.375 KB
27. Unsigned binary integer 10101101 is equal to decimal number 173, hexadecimal number AD and octal number 255
28. Given that the ASCII code of capital letter D is 68, the ASCII code of lowercase letter D is 100
29. If the byte in the memory is numbered 0000H ~ ffffh with hexadecimal number, the memory capacity is 65536; The memory capacity of the other microcomputer is 4MB, and its address must be at least 22
30. If a 2.37 million word modern Chinese dictionary is stored on a floppy disk, it needs about 3.62 1.44 MB floppy disks
31; The computer based on Neumann principle consists of five parts: input device, output device, arithmetic unit, controller and memory< There are three types of computer system bus, they are internal bus, system bus and I / O bus
33. Computer software system is divided into system software and application software
34. Multimedia technology has four characteristics: diversity, integration, interaction and digitization
35. The bridge acts on the data link layer of the OSI / RM reference model, and the router acts on the network layer of the OSI / RM reference model
1. Currency refers to a special commodity that is fixed as a general equivalent
2. Exchange rate: the system formed by the state's regulations on the relevant elements of money, the organization and management of money circulation, etc
3. Credit transaction: also known as advance transaction or margin transaction, it is a transaction mode in which the customer only pays a certain amount of margin with his own credit and entrusts the broker to buy or sell securities after obtaining the credit of the securities broker< Keynesian liquidity preference: it refers to people's psychological tendency to hold money with no income but flexible turnover, and its essence is people's demand for money
5. Inflation: under the condition of paper currency circulation, e to the excessive money supply, the purchasing power of money with the ability to pay exceeds the supply of goods, which leads to the continuous depreciation of money and the continuous rise of general price level
6. Base currency is the sum of cash held by the public in circulation and the reserves of the banking system
7. Commercial paper is a kind of written proof of creditor's rights that the creditor who provides commercial credit holds in order to guarantee the claim of debt
8. Rediscount policy: the central bank's policy provisions for commercial banks to apply to the central bank for rediscount of their unmatured bills
9. Interbank lending: the act of mutual financing between banks or between banks and non bank financial institutions in order to meet the need of insufficient temporary capital position
10. The intermediate target of money is between the final target and the operation index, which is the policy variable that the central bank can achieve with a certain degree of spirit after the monetary policy operation and transmission
11. Balance of Payments - a systematic monetary record of a country's total foreign economic transactions in a certain period of time
12. Credit is a kind of borrowing and lending behavior, a unilateral value transfer on the condition of repayment and interest payment, and a special form of value movement
13. Monetary policy is the sum of the policies and measures adopted by the central bank to adjust variables such as money, credit and interest rate in order to achieve its macroeconomic goals
14. Gresham's law, also known as the law of bad money expelling good money, means that in the case of double standard currency system, good money whose actual value is higher than the legal value is expelled from the circulation field, and bad money whose actual value is lower than the legal value is widely circulated in the market
15. Deflation is a concept corresponding to inflation. In western economics, deflation is generally defined as the continuous decline of the overall price level over a period of time
1. Briefly describe the basic functions of money
value scale, circulation means, wealth storage and payment means
2. What is the basic multiplier of money? This paper briefly analyzes the determinants of monetary multiplier
money basic multiplier, also known as money expansion coefficient, is a coefficient used to explain the multiple relationship between the total money supply and the base money. There are five determinants of money multiplier, which are the current deposit legal reserve ratio, the fixed deposit legal reserve ratio, the fixed deposit ratio, the currency ratio and the excess reserve ratio
3. Briefly describe the main factors affecting the exchange rate
a country's economic situation, balance of payments, currency circulation, interest rate and political factors, various policy factors of the government, foreign exchange control, expectation psychology, financial speculation and so on will have an impact on the change of exchange rate< How do commercial banks create credit currency? What factors restrict its ability to create deposit money
credit creation of commercial banks refers to the creation of credit currency by commercial banks through asset business such as loan and securities investment. The premise of credit creation of commercial banks is the implementation of transfer settlement and partial reserve system. The creative ability of commercial banks depends on the size of the original deposit and the influence of the statutory reserve ratio, excess reserve ratio, cash leakage ratio, statutory reserve ratio of fixed deposit and the ratio of current deposit into fixed deposit
5. What is the foundation of modern credit activities? What are the characteristics of modern credit activities
credit is a kind of lending activity, which is the performance of the relationship between creditor's rights and debt. Modern credit activities have the following characteristics: modern credit relationship has become the most common and basic economic relationship in modern economy. Secondly, in the modern economic life, risk and income are matched with each other. Thirdly, in the modern credit activities, credit tools present the trend of diversification. Fourth, modern credit activities increasingly rely on credit intermediaries and their services to rece financing risks and improve financing efficiency
6. Briefly analyze the impact of income and market interest rate on money demand
the level of income is directly proportional to the money demand. Market interest rate is inversely proportional to money demand
7. What are the indicators to determine inflation
consumer price index, wholesale special price index, GDP deflator
8< (1) the determination of monetary materials (2) the name of currency, monetary unit and price standard (3) the standard currency, subsidiary currency and their solvency (4) the issuance guarantee system
10 It shows that Keynesian monetary policy transmission mechanism theory
m ------ r ------ I ------ e ----- y
Keynesian school advocates that the main link in the transmission process is interest rate. The change or adjustment of money supply first affects the rise and fall of interest rate, then changes the investment and total expenditure, and then affects the change of total income
11. What is the base currency? What are the main channels for the central bank to supply the base money
base currency refers to the sum of the cash circulating outside the banking system and the reserves of the banking system. There are three main channels for the central bank to supply base money: (1) to the commercial banks

10. In short, a group digs bitcoin on the computer, which is equivalent to a big mine.