Ethereum private chain contract
a total of 22 weeks, divided into five stages,
the first stage is 4 weeks, go language foundation and network concurrency, learning the introctory go language,
the second stage is 4 weeks, go language practical web development, crawler development, cryptography, consensus algorithm, realizing lightweight public chain, learning the website and crawler that can develop golang, Achieve lightweight blockchain
stage 3, 4-week Ethereum source code analysis and smart contract DAPP development, master Ethereum core and smart contract development, as well as blockchain,
stage 4, 4-week super ledger, bitcoin EOS, source code analysis and smart contract practice, master super ledger development, cat bitcoin, bifurcated EOS after learning, As well as DAPP development of smart contract
phase 5, 6-week project practice, five enterprise level projects, and one year of blockchain project experience after learning
from the characteristics of the language itself, go is a very efficient language, which highly supports concurrency. Go language itself pays more attention to distributed system, and concurrency processing is relatively good, such as advertising and search, That kind of high concurrency server
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
rich standard libraries, go has built a large number of libraries, especially the network library, which is also my favorite part< As like as two peas, br / > built-in powerful tools, Go language is built with many tools chain, the best should be gofmt tools, automatic formatting code, make team review become so simple, code format is exactly the same, it is very difficult to think differently.
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:
package management: package management of go language is absolutely not perfect. By default, it has no way to make a specific version of the dependency library, nor can it create replicable builds. In contrast, python, node and Ruby all have better package management systems. However, with the right tools, the package management of go language can also perform well
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
another problem is that we may forget to handle errors. Static analysis tools such as errcheck and megacheck can avoid these errors. Although these solutions are very effective, they may not be the right way.
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with the recent sharp fluctuation of currency prices, a new profession, commonly known as "brick moving", is graally emerging in the circle. These brick moving workers pay close attention to the major bitcoin and Ethereum transactions every day. Once they find the price difference, they buy bitcoin and Ethereum from the low price and sell them from the high price to make profit
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with the increasing number of bitcoin and Ethereum transactions, according to incomplete statistics, the number of current international mainstream bitcoin transactions is graally increasing. Different from A-share and other stock markets, the stock price is globally unified. For example, the stock price of technology has the only pricing in Hong Kong stock market. However, the prices of bitcoin and Ethereum are determined by the transaction itself. Because Ethereum has a large number of transactions and different transaction volumes, the transaction price is very likely to fall. When the price fall is large, it can even reach 8% ~ 10% of Ethereum's price. At this time, many porters have the opportunity to move bricks. The so-called "brick" of moving bricks refers to Ethereum. Porters buy Ethereum from the low price and then transfer it to the high price to get the price difference
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for example, the recent sharp fluctuations in bitcoin and Ethereum markets are a good time to move bricks. Generally speaking, as long as there is a price difference of 5-50 yuan between bitcoin and Ethereum, it is worth moving bricks. However, moving bricks also requires certain transfer costs and labor costs. Sometimes, the withdrawal of bitcoin purchased from low price will not arrive so quickly. In order to speed up the transaction speed and rece the risk of price fluctuation, the porter usually has a turnover of bitcoin. For example, after purchasing bitcoin and Ethereum from a, he immediately transfers the same amount of bitcoin from his wallet to B for sale, After the completion of bilateral transactions, graally withdraw the funds into their wallets, waiting for the next time to move bricks. If you have both cash and bitcoin and Ethereum, it's the safest. You can pay at a low price and register at a high price, and then trade at the same time. The transaction can be completed in a few seconds. At this time, there is little risk in moving bricks, and what you get is pure profit. When the price of bitcoin fluctuates greatly, part of the price response is not so fast, and the profit of moving bricks is the highest
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2. Adopt large-scale high-end cloud computing, short or long currency transactions all over the world (low absorption and high selling), complete the transaction within 0.28 MS, and increase the value by floating trading point without upper limit, so as to ensure the dividend appreciation of each person
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3. They use the money of the participants to earn profits, and then give 50% to the participants, from Monday to Friday, and do not distribute on weekends. How much you earn depends on whether you have a big package or a small one
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if you have any questions, please let me know. 5: 185 plus 654 and 39360
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The public chain is open to all, the private chain is open to indivials who meet specific conditions, and the alliance chain is open to authorized organizations or institutions
public chain, also known as public blockchains, refers to a consensus blockchain that can be read by anyone in the world, sent by anyone, and effectively confirmed
private chain, also known as fully private blockchains, refers to the blockchain in which the write permission is completely in the hands of an organization, and all nodes participating in the blockchain will be strictly controlled
alliance chain, or alliance blockchains, refers to a blockchain that is managed by several organizations or institutions. Each organization or institution controls one or more nodes and records transaction data together. Only these organizations and institutions can read, write and send transaction data in the alliance chain
blockchain has three types: public chain, private chain and alliance chain
blockchain is a new application mode of distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm and other computer technologies
blockchain is an important concept of bitcoin. It is essentially a disintermediated database. At the same time, as the underlying technology of bitcoin, it is a series of data blocks generated by using cryptographic methods. Each data block contains the information of a bitcoin network transaction, Used to verify the validity of its information (anti-counterfeiting) and generate the next block
< H2 > reference: blockchain networkwhat 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
Yes, refer to the interaction between contracts. Digital currency exchange platform for example, I am trying to sign a smart contract from another factory contract and then redeploy the address of the new smart contract. However, the address it returns is the transaction hash, not the contract address. I believe this is because when the address is returned, the contract has not been exploited. When I deploy the smart contract with Web3, it seems that it will not output the contract address until the smart contract is deployed