[Learning the contract development language solidity] Use of the solidity library

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1. What is the solidity library?

The solidity library is a special contract that can be deployed like a contract, but has no state variables and cannot store ETH. The library is reusable, deployed once and reused in different contracts. Using the library can save gas and the same code does not need to be deployed multiple times.

2. How to define and use the solidity library?

Using the library keyword, the function library calls DELEGATECALL in a delegated manner. The library code is actually executed in the initiating contract.

Solidity allows you to associate a library with a new type using the using for keyword. For example, using mathLib for B

3. What are the commonly used libraries in solidity?

openzeppelin

https://github.com/OpenZeppelin/openzeppelin-contracts

ethereum-libraries

https://github.com/modular-network/ethereum-libraries

dapp-bin

https://github.com/ethereum/dapp-bin/tree/master/library iterable_mapping

Variable Map, StringUtils string comparison, linkedLisk bidirectional linked list

stringutils

https://github.com/Arachnid/solidity-stringutils