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Questions tagged [mastering-ethereum]

Content related to/ or from the book Mastering Ethereum.

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1answer
117 views

Getting error while buying test ether from https://faucet.metamask.io/

I just tried to buy a test ether from https://faucet.metamask.io but the faucet address which is supposed to give 1 ether doesn't have enough balance. Snapshot of the faucet address And when i ...
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2answers
38 views

Code Example from “Mastering Ethereum: Building Smart Contracts and DApps” doesn't work

I'm reading the Ethereum book of Gavin Wood right know and the following code example gives an error message when I try to compile it with truffle: pragma solidity ^0.4.22; contract calledContract { ...
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0answers
26 views

Can I use Flutter or Android Studio to design front end instead of using react.js and still be able to interact with ethereum?

I am new to blockchain and currently learning solidity. I have understood the concept behind blockchain and solidity is also good so far. I can design mocha tests and deploy the contract on local ...
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1answer
15 views

Trying to figure if blockchain has finished downloading.

I am working on the text, Mastering Ethereum and working on the part where one has to download the blockchain. Now I elected to use geth because parity seemed to be getting stuck on blocks for almost ...
2
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1answer
48 views

How do ethereum validate a OLD transaction(say 10k blocks ago) without sync/replay-ing the full node?

When a full node receives a freshly mined new block, it seems straightfoward how we could validate all the transactions contained in the block. As we already the current world state, we could just ...
1
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1answer
77 views

What happens to a transaction after you clicked 'send' in Ethereum network?[Transaction life cycle at the EVM and P2P networking level]?

Ref: What happens when you type in an URL in the browser So in a web browser, it's kinda easy to reason the life cycle of an HTTP request, how it moves down the network stack, reach the server, get ...
0
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1answer
14 views

Why does ethereum use only GPU for computation? Why mobile processing powers are not used?

I want to make a project based on mobile (mining) using its computing power (as done by electronium). But i am unable to find any framework or platform for that. Please help me out if anyone has a ...
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0answers
11 views

Forced data location

What is forced data location ,in the ethereum docs it says : Forced data location: parameters (not return) of external functions : calldata state variables:storage
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1answer
15 views

Dynamic Arrays of type memory

Are the dynamic arrays of type memory fixed sized. I have read that the arrays of type memory are fixed sixed. Thanks
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2answers
363 views

What is calldata?

What is calldata? I learned that there are three types of memories: Storage Memory Stack In the Ethereum docs, it says that the function parameters are of type memory by default. However, I've also ...
0
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1answer
32 views

Is there a 'geth attach' man page? [duplicate]

Is there somewhere I can find what commands can be used within geth attach, and some examples of scripts as well?
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1answer
5k views

Defining constructors as functions with the same name as the contract is deprecated. Use “constructor(…) { … }” instead [duplicate]

The warning is from running sample code from Mastering Ethereum, I get the above error and it says Use "constructor(...) { ... }" instead. function Migrations() public {