Ethereum smart contract player feast
Ethereum energy coin is not MLM
Ethereum is an open source public blockchain platform with smart contract function. Ethereum provides decentralized virtual machine (Ethereum virtual machine) to process point-to-point contract through its special cryptocurrency Ethereum
in 2013, vitalik buterin, 19, first mentioned the idea of Ethereum in a book entitled "Ethereum white paper: next generation intelligent connection and decentralized application platform". Then, in 2014, the algorithm and protocol of Ethernet coin were officially implemented, and $150 million was raised. The system itself was finally completed on July 30, 2015
as the representative of blockchain 2.0, the mainstream currency Ethernet is regarded as the wind vane of crypto digital currency market. However, over the past week, the price of ether currency has continued to fall. On August 14, 2018, the ethereal currency plummeted by 20%, reaching a record low of $257 this year. Compared with this year's peak of $1295, the price of Ethernet currency has shrunk by more than 80%. Affected by this, on August 15, 2018, none of the top ten mainstream currencies in the digital money market was spared, falling across the board, with a number of single day declines exceeding 10%
extended data
Ethereum started planning almost in 2013, and started to implement the project in 2015. Before that, there were many digital currencies imitating bitcoin in the market, and they made various modifications on the basis of bitcoin code. In this way, it is very difficult to develop a new blockchain application, to re deploy a new chain, and then to develop an application on this chain. Using a consensus mechanism of pow alone is a huge maintenance workload. It's like developing an app on a mobile phone and developing the Android system together
after Ethereum comes out, it is equivalent to the underlying operating system of the blockchain. On Ethereum, it is very convenient to develop various dapps without considering the underlying development, and it can also share the computing power and storage of Ethereum. For programmers, the threshold of blockchain development is lowered instantly. The emergence of Ethereum has played a very important role in the development and popularization of blockchain applications. That's why Ethereum is called blockchain 2.0
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
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.
Generally speaking, the steps of deploying smart contract are as follows:
- start an Ethereum node (such as geth or testrpc) Li >
- use Solc to compile smart contracts=& gt; Get the binary code Li >
- deploy the compiled contract to the network This step will consume Ethernet currency, and you need to use the default address or specified address of your node to sign the contract.)=& gt; Get the blockchain address and ABI of the contract (JSON representation of the contract interface, including variables, events and callable methods) The author confused ABI with contract interface here. ABI is the binary representation of the contract interface.) Li >
- use the JavaScript API provided by web3.js to call the contract Depending on the type of call, it may consume Ethernet currency.) li>
new type of MLM: no restrictions on personal freedom, no ID cards and mobile phones, no collective classes, but to use capital operation as a banner to pull people to cheat money, drive luxury cars, wear gold and silver, etc., attract your relatives and friends with money, and finally make you lose your money
you should be careful when paying dividends at all levels, 100% of them are
Q, someone has analyzed you.
