21 million virtual currencies in total

1. 1. According to the bitcoin mining mechanism, it will eventually be infinitely close to 21 million, but it will never be reached
it can be roughly understood as the relationship between 0.9 (9 infinite cycle) and 1
2. Even if there is only one bitcoin left in the world, it means that there are 1000 0.1 bitcoins and 100000 0.01 bitcoins in the world
let's assume that the function of bitcoin is equivalent to that of gold as a currency anchor (in fact, it also has this function). You will understand that there are 21 million bitcoins in the world and only 0.1 bitcoins in the world are the same. The currency itself or bitcoin

for example, if the number of bitcoin in the world is reced to one tenth, the market price of bitcoin should be 400000 yuan (to understand this needs a certain economic basis)

so whether bitcoin is in circulation or not has nothing to do with the quantity.

2. One of the controversial attributes of bitcoin is its fixed supply. At present, 25 new bitcoins are proced every 10 minutes, and the number is halved every four years. Overall, there won't be more than 21 million bitcoins & gt;. On the other hand, each bitcoin can be divided into 100 million shares (each is called 1 "cong"), if one cent is enough to buy a car, it will be troublesome to trade in US dollars, but even if bitcoin rises to the level of US dollars assumed above & gt; We will not encounter such problems. Therefore, in short, the total number of monetary units that will always exist is 2100 billion, that is 2100 trillion, or 250.899. In the square of choosing this value & gt; In fact, Nakamoto is much luckier or smarter than most people realize. First of all, this number is far less than 264-1, which is the largest integer that can be stored in the form of standard integer in a computer. If it exceeds that value, & gt; The value will return to zero like a odometer
secondly, however, there is a smaller threshold for the total number of "smart": the largest possible integer that can be represented in floating-point format. Integers are not the only numbers that computers can store; To deal with decimals, computers & gt; Use a format for floating point representation. Floating point notation is essentially a binary version of scientific notation. For example, here is a value you will encounter when you study physics:
mass of the earth: 5.972 1024 kg
mass of the sun: 1.989 1030 kg
speed of light: 2.998 108 M / s
light year: 9.460 1015 m
mass of proton: 1.672 10-27 kg
Planck length: 1.616 10-35 m
we can notice that, How does scientific notation allow you to represent all of these values with reasonable accuracy, even though they vary greatly in size. Floating point notation is essentially a binary scientific notation; When you store numbers & gt; When the word is 9.625, what your computer stores is "1.001101
* 1011" (in other words, it stores 0100000000100011
& gt; This is the same thing with high-precision sequence form). In this high-precision form, the coefficient (that is, the part that is not the exponent) has 52 bits. This means high precision (more refined & gt; Double precision floating point number is enough to store up to 253 numbers, but it can't be any higher. If it exceeds 253, you have to start cutting off the numbers at the end. Bitcoin's 250.9, the total number of "smart" in the form of index, is just & gt; OK, below this maximum
if we have integers, why should we care about floating-point values? Because more high-level programming languages (such as JavaScript) do not open low-level "floating point" and "integer representation", but only provide "number" representation for programmers; Concepts
– of course, in floating-point form. If Nakamoto chose 210 million instead of 21 million at that time, bitcoin programming in many languages would be much more troublesome than it is now
note that Stefan Thomas unfortunately didn't notice this in time when he wrote bitcoinjs, so that the library used a special "big number big
number" object instead of an ordinary number to store the tutorial output value; My own bifurcated bitcoin JS (along with other improvements) uses ordinary numbers.

3. The upper limit of bitcoin is not the exact figure of 21 million. 21 million is calculated according to the mining rules
in the first four years, 50 pieces were g out every ten minutes: 50 * 6 * 24 * (365 * 4 + 1) = 10519200 pieces
in the second four years, 25 pieces were g out every ten minutes: 25 * 6 * 24 * (365 * 4 + 1) = 5259600 pieces
according to the sum formula of infinite equal ratio sequence, the final total amount is infinitely close to 21038400 pieces (10519200 * 2)
as long as the mining rules are not changed, the number of bitcoins will never exceed 21038400

4. At least 0.01btc, at least 0.01btc on domestic trading websites,

at least 0.01btc on domestic trading websites,

at least 0.01btc on domestic trading websites,

at least 0.01btc on domestic trading websites,

at least 0.01btc on domestic trading websites, and at least 0.01btc on domestic trading websites

5. Cold wallet, also known as offline wallet, is a wallet that can be used without Internet connection. For example, the private key or mnemonic words are written on paper, professional hardware wallets, and some people make cold wallets with non networked devices. The advantage of using cold wallets is safety, but the disadvantage is that it is troublesome to trade and create wallets. Light wallet (SPV) SPV refers to "payment verification" rather than "transaction verification". Light wallet is a wallet implemented in thin client mode. It does not
store a complete blockchain, but only stores data related to itself. Therefore, it is small and can run on mobile phones, computers, Internet
pages, etc. The advantages of light wallet are: 1. It doesn't occupy memory; 2. It supports a variety of digital assets; 3. It has good user experience and is easy for beginners to use. The disadvantage is that transaction validation is slow.

6. Yes, when it was released, it showed that its constant number was 21 million. With the passage of time and the efforts of the miners, the number left on the market is less than 2.5 million.

7. There are not so many bitcoins in the world for you.

8. It's the second one. According to the previous block information, root node information, real-time mining time, difficulty and random value, the random string is generated by twice hash256 algorithm calculation, and is allocated and recorded when the verification is passed.

9. Limited release

10. Open source code is identity information.