Ethereum return function structure
Publish: 2021-05-05 10:39:55
1. Go full stack + blockchain course:
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.
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.
2. At the top of Ethereum is DAPP. It exchanges with the smart contract layer through Web3. JS. All smart contracts run on EVM (Ethereum virtual machine) and use RPC calls. Below EVM and RPC are the four core contents of Ethereum, including: blockchain, consensus algorithm, mining and network layer. Except DAPP, all other parts are in the Ethereum client. The most popular Ethereum client is geth (go Ethereum)
3. The token of Ethereum is proced in the process of mining, with a mining rate of 5 Ethereum coins per piece. The mining process of Ethereum is almost the same as that of bitcoin. For each transaction, miners can use the computer to run the unique title metadata of the block through hash function, and guess the answer repeatedly and quickly until one of them wins
many new users believe that the sole purpose of mining is to generate ether in a way that does not require a central issuer (see our guide "what is ether?"). It's true. The token of Ethereum is proced in the process of mining, with a mining rate of 5 Ethereum coins per piece. But mining is at least as important. Usually, banks are responsible for keeping accurate records of transactions. They make sure that money is not created out of thin air and that users don't cheat and spend money many times. However, blockchain introces a new way to keep records, the whole network instead of intermediary, to verify transactions and add them to the public ledger
Ethereum mining
although "no trust" or "trust minimization" monetary system is the goal, there are still people who need to ensure the security of financial records and ensure that no one cheats. Mining is one of the innovations that makes decentralized records possible. Miners have reached a consensus on the history of transactions in terms of preventing fraud (especially double spending on ether) - an interesting issue that hasn't been addressed before the decentralized currency works on the blockchain. While Ethereum is looking at other ways to reach a consensus on the effectiveness of the deal, mining currently keeps the platform together
how mining works
today, the mining process of Ethereum is almost the same as that of bitcoin. For each transaction, the miner can use the computer to guess the answer repeatedly and quickly until one of them wins. More specifically, the miner will run the unique header metadata (including time stamp and software version) of the block through the hash function (which will return a fixed length, unordered string of numbers and letters, which appears to be random), changing only the 'nonce value', which will affect the hash value of the result
if the miner finds a hash that matches the current target, the miner will be granted ether and broadcast the block across the network for each node to verify and add to their own ledger . If miner B finds the hash, miner a stops working on the current block and repeats the process for the next block. It's hard for miners to cheat in this game. There is no way to fake the work and come up with the right answer to the puzzle. That's why solving puzzles is called "proof of work."
on the other hand, others have little time to verify whether the hash value is correct, which is exactly what each node does. About every 12-15 seconds, a miner finds a stone. If the miner starts to solve the puzzle faster or slower than this, the algorithm will automatically re adjust the difficulty of the problem so that the miner can rebound to about 12 seconds of solution time
miners earn these ethers randomly, and their profitability depends on their luck and the computing power they put in. The specific workload verification algorithm used by Ethereum is called "ethash", which aims to require more memory, making it difficult to mine with expensive ASIC. Special mining chips are now the only profitable way to mine bitcoin
in a sense, ethash may have achieved this goal successfully, because dedicated ASIC is not available for Ethereum (at least not yet). In addition, as Ethereum aims to shift from proof of work mining to "proof of equity" (which we will discuss below), buying ASIC may not be a wise choice because it may not prove useful for a long time< However, Ethereum may never need miners. Developers plan to abandon proof of work, the algorithm currently used by the network to determine which transactions are valid and protect them from tampering to support proof of equity, which is guaranteed by token owners. If and when the algorithm is launched, proof of equity can become a means to achieve distributed consensus, and the consensus uses less resources.
many new users believe that the sole purpose of mining is to generate ether in a way that does not require a central issuer (see our guide "what is ether?"). It's true. The token of Ethereum is proced in the process of mining, with a mining rate of 5 Ethereum coins per piece. But mining is at least as important. Usually, banks are responsible for keeping accurate records of transactions. They make sure that money is not created out of thin air and that users don't cheat and spend money many times. However, blockchain introces a new way to keep records, the whole network instead of intermediary, to verify transactions and add them to the public ledger
Ethereum mining
although "no trust" or "trust minimization" monetary system is the goal, there are still people who need to ensure the security of financial records and ensure that no one cheats. Mining is one of the innovations that makes decentralized records possible. Miners have reached a consensus on the history of transactions in terms of preventing fraud (especially double spending on ether) - an interesting issue that hasn't been addressed before the decentralized currency works on the blockchain. While Ethereum is looking at other ways to reach a consensus on the effectiveness of the deal, mining currently keeps the platform together
how mining works
today, the mining process of Ethereum is almost the same as that of bitcoin. For each transaction, the miner can use the computer to guess the answer repeatedly and quickly until one of them wins. More specifically, the miner will run the unique header metadata (including time stamp and software version) of the block through the hash function (which will return a fixed length, unordered string of numbers and letters, which appears to be random), changing only the 'nonce value', which will affect the hash value of the result
if the miner finds a hash that matches the current target, the miner will be granted ether and broadcast the block across the network for each node to verify and add to their own ledger . If miner B finds the hash, miner a stops working on the current block and repeats the process for the next block. It's hard for miners to cheat in this game. There is no way to fake the work and come up with the right answer to the puzzle. That's why solving puzzles is called "proof of work."
on the other hand, others have little time to verify whether the hash value is correct, which is exactly what each node does. About every 12-15 seconds, a miner finds a stone. If the miner starts to solve the puzzle faster or slower than this, the algorithm will automatically re adjust the difficulty of the problem so that the miner can rebound to about 12 seconds of solution time
miners earn these ethers randomly, and their profitability depends on their luck and the computing power they put in. The specific workload verification algorithm used by Ethereum is called "ethash", which aims to require more memory, making it difficult to mine with expensive ASIC. Special mining chips are now the only profitable way to mine bitcoin
in a sense, ethash may have achieved this goal successfully, because dedicated ASIC is not available for Ethereum (at least not yet). In addition, as Ethereum aims to shift from proof of work mining to "proof of equity" (which we will discuss below), buying ASIC may not be a wise choice because it may not prove useful for a long time< However, Ethereum may never need miners. Developers plan to abandon proof of work, the algorithm currently used by the network to determine which transactions are valid and protect them from tampering to support proof of equity, which is guaranteed by token owners. If and when the algorithm is launched, proof of equity can become a means to achieve distributed consensus, and the consensus uses less resources.
4. The mps() function performs the same serialization as the mp() function. Instead of accepting stream objects and saving serialized data to disk files, this function simply returns serialized data
the loads() function performs the same deserialization as the load() function. Instead of accepting a stream object and reading the serialized data from a file, it accepts the str object containing the serialized data and returns the object directly.
the loads() function performs the same deserialization as the load() function. Instead of accepting a stream object and reading the serialized data from a file, it accepts the str object containing the serialized data and returns the object directly.
5. At present, their common point is blockchain + government affairs, but the application fields involve different scenarios. Personally, I don't think it's comparable. For the moment
according to the report, Zhejiang blockchain government platform is mainly engaged in blockchain bills, especially medical bills. The public platform of Changsha's SMIC blockchain mainly focuses on government information disclosure, government affairs handling, intellectual property protection, judicial expertise, finance and so on, but it has not involved the medical bills yet.
according to the report, Zhejiang blockchain government platform is mainly engaged in blockchain bills, especially medical bills. The public platform of Changsha's SMIC blockchain mainly focuses on government information disclosure, government affairs handling, intellectual property protection, judicial expertise, finance and so on, but it has not involved the medical bills yet.
6. As long as you want to learn and like it, it's never too late. Help yourself, can study well, come on, wish you good luck!!!
7. I've just seen Percy Jackson and the robber of divine fire. It's a bit like Harry Potter, but I think it's very good-looking. It's a story with Greek mythology
Percy Jackson is an ordinary 12-year-old boy who was diagnosed with dyslexia and hyperactivity disorder. During a field trip organized by the school, he was interviewed by his algebra teacher; Specific function & quot; Scared me. After that, Percy Jackson found that he was not an ordinary person, but a mythical figure and a descendant of human beings< After discovering the mystery of his life, Percy Jackson was sent to a special school. The children studying in this school are the offspring of many mythical characters. When Percy Jackson came to school, Poseidon immediately declared Jackson his own child. In this school, Percy Jackson met two good friends. One is the beautiful Annabeth chase, the descendant of Athena, the goddess of wisdom and skill; The other is Grover Underwood, a descendant of orcs. Not long in the school, Percy Jackson was accused by the gods of stealing the thunder rod of Zeus. Percy Jackson is required to hand over his thunder wand within 10 days, otherwise, his mother will be killed by these gods, and the war between the gods is inevitable...
there is still one minute left: three discriminated high school students have invented a time machine that allows them to go back in time and change their social status, And help other unfairly treated children to avoid the humiliation of discrimination in high school
twilight 2, new moon and 1 are about vampires. Bella (Kristen Stewart) is 18 years old and her father gives her a gift. Edward (Robert Pattinson) shows her love generously and tells her the legend of the Italian vampire king. Edward's red haired sister Alice (Ashley Greene, Ashley Greene) holds a birthday party specially for Bella. During the party, Bella accidentally cuts her arm and is attacked by Gaspar. Only with Edward's protection can she escape. However, since then, Edward graally alienated Bella and proposed to break up. This makes Bella cold, but Edward also has difficulties, still secretly protect Bella. Bella is in the empty window period, and her old friend Jacob (Taylor Lautner) makes a warm call, which makes their relationship warm up. Since then, Bella because of the cliff rescue, just know that Jacob is a werewolf, specialized in dealing with vampires. At the same time, Edward, who didn't know about it, thought Bella had committed suicide and was disheartened. He came to Italy to ask the royal family to end his life...
bloodthirsty daybreak, I think the ending is a little ironic
2012 is also very good, and the fantasy show of Arthur and his mini kingdom is also very good
Percy Jackson is an ordinary 12-year-old boy who was diagnosed with dyslexia and hyperactivity disorder. During a field trip organized by the school, he was interviewed by his algebra teacher; Specific function & quot; Scared me. After that, Percy Jackson found that he was not an ordinary person, but a mythical figure and a descendant of human beings< After discovering the mystery of his life, Percy Jackson was sent to a special school. The children studying in this school are the offspring of many mythical characters. When Percy Jackson came to school, Poseidon immediately declared Jackson his own child. In this school, Percy Jackson met two good friends. One is the beautiful Annabeth chase, the descendant of Athena, the goddess of wisdom and skill; The other is Grover Underwood, a descendant of orcs. Not long in the school, Percy Jackson was accused by the gods of stealing the thunder rod of Zeus. Percy Jackson is required to hand over his thunder wand within 10 days, otherwise, his mother will be killed by these gods, and the war between the gods is inevitable...
there is still one minute left: three discriminated high school students have invented a time machine that allows them to go back in time and change their social status, And help other unfairly treated children to avoid the humiliation of discrimination in high school
twilight 2, new moon and 1 are about vampires. Bella (Kristen Stewart) is 18 years old and her father gives her a gift. Edward (Robert Pattinson) shows her love generously and tells her the legend of the Italian vampire king. Edward's red haired sister Alice (Ashley Greene, Ashley Greene) holds a birthday party specially for Bella. During the party, Bella accidentally cuts her arm and is attacked by Gaspar. Only with Edward's protection can she escape. However, since then, Edward graally alienated Bella and proposed to break up. This makes Bella cold, but Edward also has difficulties, still secretly protect Bella. Bella is in the empty window period, and her old friend Jacob (Taylor Lautner) makes a warm call, which makes their relationship warm up. Since then, Bella because of the cliff rescue, just know that Jacob is a werewolf, specialized in dealing with vampires. At the same time, Edward, who didn't know about it, thought Bella had committed suicide and was disheartened. He came to Italy to ask the royal family to end his life...
bloodthirsty daybreak, I think the ending is a little ironic
2012 is also very good, and the fantasy show of Arthur and his mini kingdom is also very good
8.
#include<stdio.h>
struct
{
charstr[10];
}a[3];
intmain()
{
FILE*fp=fopen("log","r");
inti,t;
if(fp==NULL)return1;
for(i=0;i<3;i++)
{
fscanf(fp,"id.%dstring:%s ",&t,a[i].str);//读到结构体存储
printf("id.%dstring:%s ",i+1,a[i].str);//输出
}
fclose(fp);
return0;
}
9. What are the reasons for the failure of the captain? Maybe it's a matter of time.
10. rub one's eyes and wait.
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