Ethereum smart contract CSDN

2. Smart contract & quot The term "smart contract" can be traced back to at least 1995 and was proposed by the prolific interdisciplinary legal scholar Nick Szabo. He mentioned the concept of smart contract in several articles published on his website. His definition is as follows:
& quot; A smart contract is a set of promises defined in digital form, including the agreements on which the contract participants can execute these promises& quot;
let's explore the meaning of his definition in more detail
commitment
a set of commitments refers to the (often mutual) rights and obligations agreed by contract participants. These commitments define the nature and purpose of the contract. Take a sales contract as a typical example. The seller promises to deliver the goods and the buyer promises to pay a reasonable price
digital form
digital form means that contracts have to be written into computer-readable code. This is necessary, because as long as the participants reach an agreement, the rights and obligations of smart contract establishment are executed by a computer or computer network
to further explain:
(1) when will the parties to the smart contract reach an agreement? The answer depends on the specific smart contract implementation. Generally speaking, the contract is discovered when the parties are committed to the execution of the contract by installing the contract on the contract host platform< (2) contract execution
& quot; Execute & quot; And the real meaning of it also depends on implementation. Generally speaking, implementation means active implementation through technical means
(3) computer readable code
in addition, the contract needs specific & quot; Digital form & quot; Very much depends on the agreement that the parties agree to use
protocol
protocol is technical implementation, on this basis, the contract commitment is realized, or the contract commitment is recorded. Which agreement to choose depends on many factors, the most important of which is the nature of the assets being traded ring the performance of the contract
take the sales contract as an example. Suppose that the participants agree to pay in bitcoin. The chosen protocol will obviously be bitcoin protocol, on which the smart contract will be implemented. Therefore, the contract must use & quot; Digital form & quot; It's bitcoin scripting language. Bitcoin scripting language is a non Turing complete, imperative, stack based programming language, similar to forth.

3.

The smart contract has been written for a long time

if they can add changes, the description is centralized

the contract is written into the Ethereum smart contract, which is a contradiction sentence

the financial customer service doesn't understand, which is very unreliable

community sites

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go language advantages:
excellent performance, can be directly compiled into machine code, does not rely on other libraries, go is extremely fast. Its performance is similar to Java or C + +
concurrency is supported at the language level, which is the biggest feature of go. It is born to support concurrency, and go is the concurrency supported in gene, which can make full use of multi-core and make it easy to use concurrency
the built-in runtime supports garbage collection, which is one of the features of dynamic language. Although GC is not perfect at present, it is enough to cope with most of the situations we can encounter, especially GC after go1.1
it's easy to learn. The authors of go language all have the gene of C, so go naturally has the gene of C. There are 25 go keywords, but the expressive ability is very strong. It almost supports most of the features you've seen in other languages: inheritance, overloading, object, etc
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cross platform compilation and fast compilation. Compared with the sluggish compilation speed of Java and C + +, the fast compilation time of go is a major efficiency advantage
disadvantages of go language:
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lack of development framework: go language does not have a major framework, such as Ruby's rails framework, Python's Django framework or PHP's laravel. This is a heated discussion in the go language community, because many people think that we should not start with using frameworks. This is true in many cases, but if you just want to build a simple crud API, it's much easier to use Django / djrf, rails laravel, or Phoenix
exception handling: go language can help developers deal with compilation errors by simply returning errors (or call stack) through functions and expected calling codes. Although this method is effective, it is easy to lose the scope of the error, so it is difficult to provide meaningful error information to users. Error package can solve this problem by allowing us to add context and stack trace to return error
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5. Because blockchain technology has natural advantages in realizing smart contracts. Bitcoin, Ruitai, Laite, Ethereum and other digital cryptocurrencies all use blockchain technology. Blockchain is an important concept of bitcoin. In essence, it is a decentralized database and the underlying technology of bitcoin. Blockchain is a chain of uses

6. Ethereum is a distributed computing platform. It generates an cryptocurrency called ether. Programmers can write "smart contracts" on the Ethereum blockchain, and these Ethereum smart contracts will be executed automatically according to the code

what is Ethereum
Ethereum is often compared with bitcoin, but the situation is different. Bitcoin is a kind of cryptocurrency and distributed payment network, which allows bitcoin to be transferred between users

related: what is bitcoin? How does it work

Ethereum has a bigger goal. As Ethereum says, "Ethereum is a distributed platform running smart contracts.". These smart contracts run on "Ethereum virtual machine", a distributed computing network composed of all devices running Ethernet nodes

"distributed platform" means that anyone can set up and run an Ethereum node just as anyone can run a bitcoin node. Anyone who wants to run "smart contracts" on nodes must pay the operators of these nodes in ether, which is a cryptocurrency related to Ethereum. Therefore, the person running the Ethernet node provides computing power and gets paid in the Ethernet, which is similar to the way that the person running the bitcoin node provides hash power and pays in bitcoin

in other words, although bitcoin is only a blockchain and payment network, Ethereum is a distributed computing network, and its blockchain can be used for many other things. Details are provided in the Ethereum white paper

what is ether
Ethernet is a digital token (or cryptocurrency) related to Ethereum blockchain. In other words, Ethereum is the token and Ethereum is the platform. But now people often use these terms alternately. For example, coinbase allows you to buy Ethereum, which stands for Ethereum

this is technically "altcoin", which actually means a non bitcoin cryptocurrency. Like bitcoin, ether is supported by distributed blockchain - in this case, Ethereum blockchain

developers who want to create applications or Ethereum smart contracts on Ethereum blockchain need Ethernet token to pay for nodes to host it, while users of Ethereum based applications may need Ethernet to pay for services in these applications. People can also sell services outside the Ethereum network and accept Ethernet payments, or they can sell Ethernet tokens in cash - just like bitcoin

8. Not necessarily, but Ethereum has no upper limit, which is really good

9.

Solidness language is a special language for writing and executing smart contracts. It is a contract oriented high-level language running on the basis of Ethereum virtual machine. It was first proposed by the former CTO and co-founder Gavin wood of Ethereum in August 2014. Later, Ethereum developers set up a special team to continuously improve solidness language, At present, it is still under development and optimization. The development storage area on GitHub is HTPs / github.com/thereum/solidness. Here we can learn the most comprehensive details and related documents about the development and iteration process of solidness language. In terms of language style, solid language is deeply influenced by C + +, Python and JavaScript. It is a static programming language, compiled in bytecode mode, so it can run on Ethereum virtual machine. Gavin wood uses the syntax rules of ECMAScript scripting language of JavaScript for reference when developing solid language, which makes it somewhat similar to the existing web development language, but it is quite different. For example, solid language has static type, variable return function and so on. The most important point is that solid language can write contracts with self executing business logic and embedded in smart contracts. Therefore, it is not only one of the basic programming languages of Ethereum, but also the basic programming languages of most other Ethereum based blockchain procts (blockchain 2.0) with smart contracts, It is widely used in the vast majority of blockchain procts, such as hyperledger project, which is developed with soliditv language

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