{"id":1179,"date":"2022-12-16T05:06:28","date_gmt":"2022-12-16T05:06:28","guid":{"rendered":"https:\/\/dodona.software\/?p=1179"},"modified":"2022-12-16T05:06:28","modified_gmt":"2022-12-16T05:06:28","slug":"intro-to-solidity-a-simple-hello-world-smart-contract-ethereum-developer-tutorial-for-beginners","status":"publish","type":"post","link":"https:\/\/brandweaver.ai\/blog\/intro-to-solidity-a-simple-hello-world-smart-contract-ethereum-developer-tutorial-for-beginners\/","title":{"rendered":"Intro to Solidity: A Simple, Hello World Smart Contract &#8211; Ethereum Developer Tutorial for Beginners"},"content":{"rendered":"\n<p>In this post, we create a simple &#8220;hello world&#8221; smart contract, compile it, and deploy it to your local chain. We also cover basics, such as declaring a license type, <code>pragma solidity<\/code> version numbers, and declaring a public variable. We hope you enjoy it!<\/p>\n\n\n\n<figure class=\"wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<div class=\"ast-oembed-container\" style=\"height: 100%;\"><iframe loading=\"lazy\" title=\"Intro to Solidity: A Simple, Hello World Smart Contract - Ethereum Developer Tutorial for Beginners\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/nwV-OgKNIug?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" allowfullscreen><\/iframe><\/div>\n<\/div><\/figure>\n\n\n\n<h1 class=\"wp-block-heading\">The Simplest Smart Contract<\/h1>\n\n\n\n<p>Let&#8217;s write the simplest smart contract: Hello World \ud83d\udc4b \ud83c\udf0e  First, create a new Solidity file called, <code>HelloWorld.sol<\/code>. I did this by simply copy-pasting an existing .sol file, but you can always start from scratch if you prefer. <\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Name the contract, HelloWorld<\/h2>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"382\" src=\"https:\/\/brandweaver.ai\/wp-content\/uploads\/2022\/12\/image-13-1024x382.png\" alt=\"\" class=\"wp-image-1180\" srcset=\"https:\/\/brandweaver.ai\/wp-content\/uploads\/2022\/12\/image-13-1024x382.png 1024w, https:\/\/brandweaver.ai\/wp-content\/uploads\/2022\/12\/image-13-300x112.png 300w, https:\/\/brandweaver.ai\/wp-content\/uploads\/2022\/12\/image-13-768x286.png 768w, https:\/\/brandweaver.ai\/wp-content\/uploads\/2022\/12\/image-13.png 1086w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>We&#8217;ll write the Solidity code in between the curly braces (starting at line 7, above). But first, let&#8217;s briefly describe what&#8217;s going on in lines 1-2. <\/p>\n\n\n\n<h2 class=\"wp-block-heading\">License Declaration<\/h2>\n\n\n\n<p>The first line is a license declaration. Your code will compile without a license declaration, but if you don&#8217;t put a license, the compiler will emit warnings. I don&#8217;t like warnings, so let&#8217;s add either UNLICENSED or MIT (a permissive, open-source license). <\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Solidity Compiler Version Declaration<\/h2>\n\n\n\n<p>In line 2, we specify the compiler version. I set it to Solidity <code>^0.8.17<\/code>. If you want to target a compiler version that is greater than or equal to 0.8.17, you include a carrot <code>^<\/code>, which tells the Solidity compiler that this contract is meant for compiler greater than or equal to 0.8.17.\u00a0It is considered good practice to set the compiler version to a specific number, especially when deploying to mainnet so that future versions (which may include breaking changes) don&#8217;t wreck your code. <\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Adding a String to your smart contract<\/h2>\n\n\n\n<p>In line 6, <code>contract HelloWorld{}<\/code> is the simplest Solidity contract there is. But it&#8217;s rather uninspiring because it does nothing at all. So let&#8217;s spice things up \ud83c\udf36 <\/p>\n\n\n\n<p>To add a string inside this smart contract, at line 7, type:<\/p>\n\n\n\n<p><code>string public someString = \"Hello World!\";<\/code><\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"350\" src=\"https:\/\/brandweaver.ai\/wp-content\/uploads\/2022\/12\/image-14-1024x350.png\" alt=\"\" class=\"wp-image-1181\" srcset=\"https:\/\/brandweaver.ai\/wp-content\/uploads\/2022\/12\/image-14-1024x350.png 1024w, https:\/\/brandweaver.ai\/wp-content\/uploads\/2022\/12\/image-14-300x102.png 300w, https:\/\/brandweaver.ai\/wp-content\/uploads\/2022\/12\/image-14-768x262.png 768w, https:\/\/brandweaver.ai\/wp-content\/uploads\/2022\/12\/image-14.png 1078w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>The <code>string public<\/code> declaration means that anyone can read the SomeString variable after we deploy the smart contract on chain.  The second part sets the variable <code>someString<\/code> to &#8220;Hello World!&#8221; Now compile this contract and deploy it via Terminal by executing <code>npm run deploy<\/code>:<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"256\" src=\"https:\/\/brandweaver.ai\/wp-content\/uploads\/2022\/12\/image-15-1024x256.png\" alt=\"\" class=\"wp-image-1182\" srcset=\"https:\/\/brandweaver.ai\/wp-content\/uploads\/2022\/12\/image-15-1024x256.png 1024w, https:\/\/brandweaver.ai\/wp-content\/uploads\/2022\/12\/image-15-300x75.png 300w, https:\/\/brandweaver.ai\/wp-content\/uploads\/2022\/12\/image-15-768x192.png 768w, https:\/\/brandweaver.ai\/wp-content\/uploads\/2022\/12\/image-15-1536x383.png 1536w, https:\/\/brandweaver.ai\/wp-content\/uploads\/2022\/12\/image-15.png 1591w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>Finally, test that the smart contract does what you expect.\u00a0Load the contract in Sidekik and verify that you can read <code>someString<\/code>. Do that by clicking on the blue button, <em>someString<\/em>. Sidekik should return the output value, &#8220;Hello world!&#8221;<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"228\" src=\"https:\/\/brandweaver.ai\/wp-content\/uploads\/2022\/12\/image-16-1024x228.png\" alt=\"\" class=\"wp-image-1183\" srcset=\"https:\/\/brandweaver.ai\/wp-content\/uploads\/2022\/12\/image-16-1024x228.png 1024w, https:\/\/brandweaver.ai\/wp-content\/uploads\/2022\/12\/image-16-300x67.png 300w, https:\/\/brandweaver.ai\/wp-content\/uploads\/2022\/12\/image-16-768x171.png 768w, https:\/\/brandweaver.ai\/wp-content\/uploads\/2022\/12\/image-16-1536x341.png 1536w, https:\/\/brandweaver.ai\/wp-content\/uploads\/2022\/12\/image-16.png 1849w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>Congrats on completing another step in your Solidity programming language journey. Stay tuned for the next post, where we demonstrate how to build a simple counter. There, we&#8217;ll introduce the concept of read and write functions.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In this post, we create a simple &#8220;hello world&#8221; smart contract, compile it, and deploy it to your local chain. We also cover basics, such as declaring a license type, pragma solidity version numbers, and declaring a public variable. We hope you enjoy it! The Simplest Smart Contract Let&#8217;s write the simplest smart contract: Hello &hellip;<\/p>\n<p class=\"read-more\"> <a class=\"\" href=\"https:\/\/brandweaver.ai\/blog\/intro-to-solidity-a-simple-hello-world-smart-contract-ethereum-developer-tutorial-for-beginners\/\"> <span class=\"screen-reader-text\">Intro to Solidity: A Simple, Hello World Smart Contract &#8211; Ethereum Developer Tutorial for Beginners<\/span> Read More &raquo;<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_uag_custom_page_level_css":"","site-sidebar-layout":"default","site-content-layout":"default","ast-global-header-display":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","footnotes":""},"categories":[13],"tags":[14,7,8],"featured_image_src":null,"featured_image_src_square":null,"author_info":{"display_name":"Rod Fuentes","author_link":"https:\/\/brandweaver.ai\/blog\/author\/rodsidekik-xyz\/"},"uagb_featured_image_src":{"full":false,"thumbnail":false,"medium":false,"medium_large":false,"large":false,"1536x1536":false,"2048x2048":false,"gb-block-post-grid-landscape":false,"gb-block-post-grid-square":false},"uagb_author_info":{"display_name":"Rod Fuentes","author_link":"https:\/\/brandweaver.ai\/blog\/author\/rodsidekik-xyz\/"},"uagb_comment_info":612,"uagb_excerpt":"In this post, we create a simple &#8220;hello world&#8221; smart contract, compile it, and deploy it to your local chain. We also cover basics, such as declaring a license type, pragma solidity version numbers, and declaring a public variable. We hope you enjoy it! The Simplest Smart Contract Let&#8217;s write the simplest smart contract: Hello&hellip;","_links":{"self":[{"href":"https:\/\/brandweaver.ai\/wp-json\/wp\/v2\/posts\/1179"}],"collection":[{"href":"https:\/\/brandweaver.ai\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/brandweaver.ai\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/brandweaver.ai\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/brandweaver.ai\/wp-json\/wp\/v2\/comments?post=1179"}],"version-history":[{"count":0,"href":"https:\/\/brandweaver.ai\/wp-json\/wp\/v2\/posts\/1179\/revisions"}],"wp:attachment":[{"href":"https:\/\/brandweaver.ai\/wp-json\/wp\/v2\/media?parent=1179"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/brandweaver.ai\/wp-json\/wp\/v2\/categories?post=1179"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/brandweaver.ai\/wp-json\/wp\/v2\/tags?post=1179"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}