Ethereum addresssend

1.

If you want to query the transaction records on the main network, you can use Etherscan. However, if you build your own private chain, how should you query the transaction records

the answer is that you need to listen to the logs on the chain, save them in the database, and then query them in the database. For example:

< pre t = "code" L = "Java" > varaddr = & quot& quot;< br />varfilter=web3.eth.filter({fromB lock:0 ,toBlock:' latest', address:addr });< br />filter.get(function(err,transactions){
transactions.forEach(function(tx){
vartxInfo=web3.eth.getTransaction(tx.transactionHash);
/ / at this time, the transaction information txinfo can be stored in the database
})< br />});

Web3. Eth. Filter() is used to monitor the log on the chain, and Web3. Eth. Gettransaction() is used to extract the information of the specified transaction. Once the transaction information is obtained, it can be stored in the database for query

recommend a practical introction, you can see: Ethereum tutorial

2. Return the result of ifconfig
eth0 to awk for processing
where - F & # 39;:|< br />+'
this is a separator defined by awk and then matched with "BCAST & quot;, Take the content of the fourth column
since your command is not universal, you can't output the result here, but you should intercept the broadcast address

3. 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

4. The following answers are expected to help you:
blockchain is a new application mode of computer technology such as distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm, etc
the so-called consensus mechanism is a mathematical algorithm to establish trust and obtain interests between different nodes in the blockchain system

in a narrow sense, blockchain is a kind of chained data structure that combines data blocks in chronological order in a sequential way, and it can not be tampered with and forged by cryptography

broadly speaking, blockchain technology uses blockchain data structure to verify and store data, uses distributed node consensus algorithm to generate and update data, and uses cryptography to ensure the security of data transmission and access It is a new distributed infrastructure and computing method to program and operate data by using intelligent contract composed of automated script code

advantages:

1) the algorithm is simple and easy to implement
2) there is no need to exchange additional information between nodes to reach a consensus
3) it takes a lot of cost to destroy the system< Disadvantages:

1) waste of energy
2) it is difficult to shorten the block confirmation time
3) the new blockchain must find a different hash algorithm, otherwise it will face bitcoin attack
4) it is easy to generate bifurcation and needs to wait for multiple confirmations
5) there is no finality, and checkpoint mechanism is needed to make up for it
blockchain is a kind of distributed shared accounting technology. What it needs to do is to enable all parties involved to establish a trust relationship at the technical level. Blockchain can be roughly divided into two levels, one is to do the underlying technology of blockchain; The second is to do the upper application of blockchain, that is, the transformation, optimization or innovative application based on blockchain
blockchain has been applied in several fields. In the first field of digital assets, in addition to some points and check-in cards we see, it also includes a variety of other assets, including the process of asset digitization
the second area is trade finance, because trade finance is originally a way of multi link participation and multi-party participation, blockchain can greatly improve the efficiency of the middle, making many of the original procts achieve the effect of substitutes
the third area uses equity, which is the company's equity. Like some regional equity trading centers, the purpose is to solve the convenience between equity and trading, and to make a relatively convenient circulation. At present, the multi center blockchain system can indeed improve efficiency and rece costs.

5. For now, if there are development documents, you need to get them according to the development documents. If not, there is no way

I hope my answer can help you. If you don't understand anything, you can ask.

6. This is an ARP conflict. I don't know what your actual physical connection is
in general, when DHCP automatically obtains IP, the router is connected to the router, and the LAN port IP of the two routers is the same, or the IP of the two routers is different, but the DHCP service is turned on, then the above phenomenon will appear
or if the computer is plugged in with portable WiFi, such as 360 portable WiFi, which gets 192.168.1.1 by default, it will cause ARP conflict with ip192.168.1.1 of your router
there are two ways to connect the two routers:
1 the second router turns off DHCP and changes the LAN port IP address to a different IP from the LAN port IP of the main router
then connect the LAN ports of two routers at both ends of the network cable
2 another method is that the second router turns off DHCP, selects WAN port, selects fixed IP for broadband type, and sets the fixed IP to be different from the LAN port IP of the main router
the LAN port IP of the second router is changed to a network segment IP different from the LAN port IP of the main router
then the two ends of the network cable are respectively connected to the LAN port of the first router and the WAN port of the second router

7.

Hello, many examples are that eth. Getcompilers() returns solidity or configures Solc

and then reports error: the method eth_ Getcompilers does not exist / is not available error

because this method has been removed after 1.6, and it is not advisable to use lower version geth

solution:

< UL >

start an Ethereum node (such as geth private chain or testrpc)

compile smart contracts with Solc

the compiled contract is deployed to the network

the JavaScript API provided by eb3.js is used to call the contract Depending on the type of call, it may consume Ethernet currency.)

< / UL >

hope to help you

8. In 1903, the Wright brothers designed and built a successful flight in the United States. This is the first time that the world's aircraft is heavier than aerodynamic and maneuverable flight. During the first World War, the aircraft had been used in combat. When the aircraft reached 180 to 220 km / h, the speed of 6000 lift limit reached 7000 men, ranging from 400 to 450 km, and the payload of 1000 to 2000 kg bombers. In World War II, the aircraft reached speeds of 750 km / h, up to 10 tons of payload bombers. After the mid-1940s, with the development of piston jet engine, the flight performance of aircraft improved significantly. In the 1980s, there were more than 30000 square meters on the ceiling of the aircraft, the maximum speed of sound was more than three times, the range was more than 20000 km, and the maximum load was more than 100 tons. The future development trend is to further improve the speed of aircraft (some countries are considering the development of supersonic jet) and supersonic flight performance, improve the performance and safety of aircraft, improve the maintenance safety performance and improve the economy (especially rece the life-cycle cost). The development of trans atmospheric vehicles is also a trend worthy of attention. In 1877, the Wright brothers invented the airplane in winter, a heavy snow in Dayton, the United States, on the outskirts of the mountains full of white. A group of children came to the hillside with thick snow and quickly slid down with their self-made plow. There was a burst of laughter on the hillside. Next to them, two boys were speechless, watching from top to bottom through the cheerful sleigh. The big little boy cried out:!! Hey, if only we had a plow. "Another child pouted and said," Dad always tells us not to live at home. "He had an idea, and then said," brother, let's do it ourselves. "The child told his brother to listen, and then he laughed and said happily:“ Yes, we can do it ourselves, Orwell, let's go back. "So the two kids hobbled down the hill and ran to the house. The brothers are the Wright brothers. Wilbur's name is big and small. It's Orville. They have the habit of playing some things and often play all kinds of games. Their grandfather was a craftsman who made wheels. There were all kinds of tools in the house. The two brothers used it as their playground and often went to see my grandfather's work. As time goes on, they will imitate and make some small toys. So the two brothers decided to do this time limit plow and pull to a hillside with other games. In the evening, the two brothers told his mother the idea. Mom was very happy and said, "OK, let's do it together." so the two brothers went to my grandfather's studio and found that a lot of wood and tools would be exhausted without hesitation“ No, "mom said to stop them," if there's a plan for something, we'll draw a pattern first and then do it! " Brothers can understand this truth as soon as they read it. We are together with mom's design drawings. The size of the fuselage for the brother's mother introction, and then draw a very short sled“ Mom, other people's plow is very high. Why is your painting so short? Is that ok? " He asked his brother Orwell“ My child, it's called "sled running fast". You've been very short, which can rece the wind resistance. The speed will be much faster. " Mother explained gently. The same is true in a brother, which should not do any rash, should first understand the truth. A day later, the Wright brothers made a bobsled. The brothers dragged it to the hillside, where a boy came“ Come on, brother Wright, bring a monster The little boy was crying and writing. Soon, the children all gathered around and signed to talk about this strange thing. Wright brothers disapprove, bravely said: "who cooperate with us!" The boy who ran earlier called out: "I'm coming, I'm competing with them!" Then he pulled his sled over. Of course, as a result of the race, the Wright brothers won, and the children no longer scoffed at the sleigh, but protected left and right, it seemed to want to find something. The Wright brothers are very happy to go home with the joy of victory. At Christmas, my father came back from other places. On Christmas morning, my father gave them presents. The brother, who was eager to open his watch, was an unknown toy and looked strange. Dad told them that it was a spiral flight, also flying high in the air“ Birds can fly! How can you fly Wilbur was skeptical. Dad laughed and performed on the spot. I saw him for the first time, the twisted rubber band is good, let go, it makes a whine sound, flying high in the air. Brother, I believe that in addition to birds and butterflies, some human beings can also fly into the sky. So the two brothers brought it to the work, from which you want to explore it, why it can fly. From this point of their young hearts, something that sprouts for the future can fly high in the blue sky. This desire has affected them. In 1896, the Wright brothers saw a piece of news in the newspaper: the gliding plane crash in Germany was e to the death of the driver. The news was a big shock to them, and the two brothers decided to learn to fly. At this time, the Wright brothers opened a bicycle shop. Although they work to make money, they develop flight information. Three years later, they decided to have a great understanding of aviation paragliders. They first observed the action of eagles flying in the air, and then painted one by one, only at the beginning of the design of the glider. In October 1900, the Wright brothers finally got their first glider and took it far away from here. Little Eagle Beach is very remote, with neither trees nor surrounding houses. It's windy and very suitable for flying gliders. This pair of brothers spent a week. When the glider was installed, the rope was tied first, so it was like a kite flying, and the result was successful. Then I sat in Wilbur's test. Although I flew up, I was only one meter tall. The next year, on the basis of the brothers' last time, after many improvements, they also made a glider. This fall, they went to Xiaoying beach, trial, all of a sudden reached 180 meters high. The brothers are very happy, but not satisfied. Do they want to build a wind turbine that can fly? The brothers repeatedly thought, put together about flying, repeatedly studied, and always felt that there was something powerful in the pet glider and the Sudan People's liberation movement into the air. One day, a taxi company stopped in front of the driver and asked them to use a tool. Repair the engine of a car. The brothers have an idea that they can't use the engine of a car to drive an airplane. From this point, the two brothers used their brains to start a maneuver. They first measured a maximum glider capacity of 90 kg, so they ordered no more than 90 kg engine factory. But it's the lightest engine for 190 kg, and there's no law out there for such a light engine rule factory. Later, the engine engineer manufacturer learned about the incident and agreed to help the Wright brothers. After a while, engineers really created a 12 horsepower, 70 kg gasoline engine. The brothers were very happy and soon began to study how to use the engine to drive the glider. After numerous tests, they finally put the engine on the glider, but installed the glider on the propeller to drive the propeller from the engine to drive the glider. In September 1903, the Wright brothers flew, and they flew again to Kitty Hawk beach with an engine. Although the experiment failed, they learned a lot. Soon after, they kept testing many times, not because of propeller failure, but because of faulty engine or driving problems. Wright's face was embarrassed, but he still insisted on flying. Just then, a mingjiaolanlai inventor, commissioned by the U.S. government, created a gasoline engine for an airplane that crashed into the sea in a test flight. After the Wright brothers learned the news, they went to investigate and learned a lesson from lanlai's failure and accumulated rich experience. They made a strict inspection on every member of the plane and formulated strict operation requirements. On December 14, 1903, they went to the Kitty Hawk for flight test. In the afternoon of the same day, the first two tracks placed on the ground by the wooden brothers were inclined to make it easy for the plane to slide. Then, put them on the plane, put them on the track. In the end, who should fly? The brothers have no choice but to toss a coin and let Wilbur fly first. Wilbur on the ship, the plane in the middle, and they launched the plane, the engine came roaring, propeller also slowly turn up. The plane taxied only three meters on the ramp, and at the same time, it broke the line on the back and roared into the air“ It's flying Ovi exclaimed excitedly. Before the voice fell, the plane slowed down suddenly and fell to the ground quickly. The whole flight took less than four minutes. Ovi came running. Webb jumped out of the fallen plane, and the brothers quickly observed the plane. The plane was not damaged“ What's the problem? " Brothers discuss and check one by one. There is no mistake. The engine and propeller rotate very well. The technical operation is completely correct“ Big brother, I know why, "Ovi said when smiling." we use the ramp taxiing, only three meters away from the plane to take off, and then the rotating propeller has not reached a very high speed.!, So, although under the plant "" yes, "Wilbur nodded for sure, and then said," we can't use the glide way to close, we can fly by the power of the propeller. That's it. The guide rail is installed in a flat place, so try it“ They worked three days in a row, and the track was placed on a plane. At 10 a.m. on December 17, 1903, the sky was overcast and dark. The brothers were invited to watch the farmer's fearing flight and urged them to fly quickly. Flying by Orville, he climbed onto the plane and crawled in the pilot's seat. At the same time, the engine began to roar and the propeller began to turn. All of a sudden, the plane skidded, suddenly rose to three meters high, and then flew to the level“ Fly here! Fly here Several farmers cheered up and as Wilbur, the back of the plane caught up. After a 30 meter flight, it took root. Wilbur rushed forward and ran excitedly. The plane had just climbed out. Who was his brother? He cried out in tears!! We succeeded in our success, "45 minutes later, Wilbur flew to a flying distance of 52 meters, and for a while, orvey flew another flight, 59 seconds, with a distance of 255 meters. This is the first time in human history that the Wright brothers reported a successful airplane flight to the newspaper. The newspaper can not believe that there is such a thing and refuse to release information. The Wright brothers didn't care. Keep improving your airplane. Soon, the brothers also made a plane that could take two people and fly in the air for more than an hour. After the news spread, people rushed to tell him that the U.S. government attached great importance to it, and Wright decided to do a pilot flight show. On September 10, 1908, the weather was unusually clear, and the plane was looking at people everywhere