truffle | Crafted with the finest cacaos | Blockchain library

Solidity currently (v0.8) doesn't have a way to tell that a class (a contract) implements an interface. Instead, the is keyword is used to mark an inheritance, as "derives from".

So the CpayCoin is IERC20 expression marks the CpayCoin as a child and IERC20 as a parent - not as an interface.

The IERC20 (parent) defines few functions (e.g. decimals() and transfer()) that the CpayCoin (child) doesn't implement, which makes the CpayCoin an abstract class.

Solution:

Implement in CpayCoin all functions defined in the IERC20 interface to not make it an abstract class, and to make it follow the ERC-20 standard. Then you're free to remove the inheritance as it becomes redundant.

Or just remove the inheritance to not have any unimplemented function definitions (but then the contract won't follow the ERC-20 standard).

Mind that in your current code, the _transfer() internal function is unreachable. I'd recommend to implement a transfer() external function that invokes this internal _transfer().

Here are some references that might help:

Try installing Truffle via PowerShell in Admin mode (very important that you're in Admin mode)

You'll need to allow scripts to run as an Admin in PowerShell. To do this, here are some references in the threads in Stack Overflow:

Enable Execution of PowerShell Scripts

PowerShell Scripts

Cannot Install Truffle

I ran the command Set-ExecutionPolicy -Scope CurrentUser -ExecutionPolicy Bypass -Force in PowerShell to get this to work, but please reference the threads above before doing this.

If you use Uniswap platform to swap a token, you are going to have 2 steps. You are going to approve the token, in this step metamask will pop-up and you are going to confirm it. Then Uniswap will do the actual swap, it takes the tokens out of your wallet and does the exchange for you.

This is the swapExactETHForTokens function

I had the same problem today. Fixed it by using the Websocket endpoint wss://bsc-ws-node.nariox.org:443 from the smart chain docs https://docs.binance.org/smart-chain/developer/rpc.html

You have to install Visual Studio Community 2022 as well as Visual Studio Code. And when installing Visual Studio Community, you have to install desktop development with C++ with some optional packages.

Using a local testnet allows you to control very precisely the state of the blockchain during your test. However, it will require you to deploy every contract you need manually.

A fork of the mainnet will save you from having to deploy every contract already deployed on the mainnet. However you will sacrifice control over the environment and will require a connection to a node.

I've deployed Uniswap 2V on a testnet a few times. To do it you will need the bytecode and ABI for the following contracts: UniswapV2Factory, UniswapV2Pair, UniswapV2Router02 (I suppose you want the second version of the router). The Uniswap docs explains very well how to download them from NPM. For the router to work properly you will also need to deploy a WETH contract. I suggest deploying the one from this github page.

Before running this code, just make sure that your chain is running. For hardhat run the following command:

If you are installing it using npm package manager. Downgrade your npm to 7.24.2 it worked for me I hope it will also work for you. Use the following command to downgrade npm

Lambda should be the average frequency, but taking mean(trufflesTable) returns the average of the counts of frequencies. Use mean(trufflesFound) instead. The reason the second one looks "right" is because mean(extinctData) is relatively close to mean(extinctFreqTable). Note that the probabilities don't sum exactly to 1, because given the mean it is conceivable that we'd observe more than 4 truffles in a future search area.

in compile.js