August 2018
Intermediate to advanced
404 pages
11h 19m
English
Content preview from Ethereum Cookbook
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How to do it…
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Let's consider a lottery system that selects the winning numbers based on a future block hash. While buying a ticket, the user is asked to guess a random set of numbers and is validated against some future block. The prize is given based on how accurate the prediction was.
- Create a contract by specifying the solidity version and a name:
pragma solidity ^0.4.17;// Decentralized autonomous lotterycontract DAL { // ...}
- Create a data structure that will store the bet details of each user. Include the bet amount, guessed number, and a future block number to validate the bet against. Also, create a mapping that maps each bet against a user address:
struct Bet { // Bet amount uint256 value; // Guessed numbers uint32 betHash; ...Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.