3
votes
Implement smart contract that can spend user's tokens with just one approve
This is part of the ERC20 specification.
See here, the transferFrom() function. https://eips.ethereum.org/EIPS/eip-20#methods
Users send a transaction to the token contract to approve your contract to ...
- 54.8k
2
votes
Implement smart contract that can spend user's tokens with just one approve
As Rob Hitchens said, this is an already existing feature of Erc20 tokens. However, i would like to add that you can't do that with ETH, since it's not a token. But you can do this with wrapped eth, ...
- 56
2
votes
Eth price dont update after another function iteration
Ethereum generates a new block every ~12 seconds. All on-chain data remains the same during the interval. So, it is normal to have no updates in 5 seconds.
- 81
1
vote
Avoiding loops in Solidity for a simple situation
Looping through all users is not just very gas inefficient, it may become impossible once your contract has a lot of users and the looping consumes more gas than the block gas limit.
I would recommend ...
- 118
1
vote
Prices on Dexes
Price can change only between blocks. On ethereum a block lasts 12 seconds, during which the price doesn't change. Also if no trade happens in a block, the price still doesn't change.
You're ...
- 2,774
1
vote
Accepted
What's the best way to raise a number to the power of a fractional exponent in Solidity
You can achieve this with the pow function of PRBMath. Here's an example:
pragma solidity >=0.8.22;
import { UD60x18, ud } from "@prb/math/src/UD60x18.sol";
contract Foo {
function ...
- 17.3k
1
vote
Accepted
How to decode storage value of a struct
First of all, a struct is just the logical grouping, from the storage perspective the structs can be omitted. So just the variables/property types define how the storage is packed.
A slot occupies ...
- 2,004
1
vote
Adding Uniswap interface to a ERC20 token smart contract
Some tokens create their a token pair and register it with uniswap. They implement some form of integration with the token pair, like charging a percentage for fees or dynamically adjusting the token ...
- 31k
1
vote
Accepted
Im trying to build a cryptocurrency(USD tether just like USD) that works with ethereum and polygon,
The simplest way to create a token with solidity is to inherit ERC20 contract and add whatever features you want.
https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/...
- 81
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