{"id":7558,"date":"2025-07-05T00:44:26","date_gmt":"2025-07-04T19:14:26","guid":{"rendered":"https:\/\/namastedev.com\/blog\/?p=7558"},"modified":"2025-10-02T11:47:11","modified_gmt":"2025-10-02T06:17:11","slug":"introduction-to-stack-queues","status":"publish","type":"post","link":"https:\/\/namastedev.com\/blog\/introduction-to-stack-queues\/","title":{"rendered":"Introduction to Stack and Queues"},"content":{"rendered":"\n<!-- PrismJS for Syntax Highlighting -->\n<link href=\"https:\/\/cdn.jsdelivr.net\/npm\/prismjs@1.29.0\/themes\/prism-tomorrow.min.css\" rel=\"stylesheet\"\/>\n<script src=\"https:\/\/cdn.jsdelivr.net\/npm\/prismjs@1.29.0\/prism.min.js\"><\/script>\n<script src=\"https:\/\/cdn.jsdelivr.net\/npm\/prismjs@1.29.0\/plugins\/autoloader\/prism-autoloader.min.js\"><\/script>\n\n<style>\n.wp_blog_theme {\n  --primary: #E58C32;\n  --secondary: #030302;\n  --light-bg: #fef9f4;\n  --text-dark: #2d2d2d;\n  --tab-radius: 12px;\n  --shadow: 0 4px 12px rgba(0, 0, 0, 0.08);\n  --code-bg: #001f3f;\n  --code-text: #d4f1ff;\n}\n\n.wp_blog_container {\n  font-family: 'Segoe UI', sans-serif;\n  background: var(--light-bg);\n  margin: 0;\n  padding: 0;\n  color: var(--text-dark);\n}\n\n\/* Heading *\/\n.wp_blog_main-heading {\n  text-align: center;\n  font-size: 2.4rem;\n  color: var(--primary);\n  margin-top: 2.5rem;\n  font-weight: bold;\n}\n\n\/* Explanation Card *\/\n.wp_blog_explanation,\n.wp_blog_code-tabs-container {\n  max-width: 940px;\n  margin: 2rem auto;\n  padding: 2rem;\n  background: white;\n  border-radius: var(--tab-radius);\n  box-shadow: var(--shadow);\n}\n\n\/* Text and Visuals *\/\n.wp_blog_explanation h2 {\n  font-size: 1.4rem;\n  color: var(--primary);\n  margin-bottom: 0.5rem;\n}\n\n.wp_blog_explanation p,\n.wp_blog_explanation li {\n  font-size: 1.05rem;\n  line-height: 1.7;\n  margin: 0.5rem 0;\n}\n\n.wp_blog_explanation code {\n  background: #fef9f4; 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\/* makes it the reference for absolute children *\/\n}\n\n.wp_blog_toggle-btn {\n  position: absolute;\n  top: 1rem;\n  right: 1rem;\n  z-index: 9999;\n  padding: 0.5rem 0.8rem;\n  border-radius: 10%;\n  background: var(--primary);\n  color: white;\n  font-weight: bold;\n  cursor: pointer;\n  border: none;\n  box-shadow: var(--shadow);\n  transition: background 0.3s, transform 0.2s;\n}\n\n.wp_blog_toggle-btn:hover {\n  background: #cc772e;\n}\n\n.wp_blog_theme.dark-mode .wp_blog_code-tabs-container {\n  background: #1e1e1e;\n}\n<\/style>\n\n<div class=\"wp_blog_container wp_blog_theme\">\n<button id=\"blogNotesThemeToggle\" class=\"wp_blog_toggle-btn\">\ud83c\udf19<\/button>\n  <h1 class=\"wp_blog_main-heading\"><\/h1>\n\n  <div class=\"wp_blog_explanation\">\n    <h2>What is a Stack?<\/h2>\n    <p><strong>Stack<\/strong> follows the <code>LIFO (Last-In-First-Out)<\/code> principle. The last element added is the first one to come out.<\/p>\n\n    <h3>Stack Operations<\/h3>\n    <ul>\n      <li><strong>Push:<\/strong> Add an element to the top<\/li>\n      <li><strong>Pop:<\/strong> Remove the top element<\/li>\n      <li><strong>Peek\/Top:<\/strong> View the top-most element<\/li>\n    <\/ul>\n\n  <h2>Visualisation:<\/h2>\n    <img decoding=\"async\"\n        src=\"https:\/\/namastedev.com\/blog\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-05-at-12.45.14\u202fAM.png\"\n        alt=\"stack\"\n    \/>\n        \n\n    <h3>Example Flow<\/h3>\n    <ul>\n      <li><code>stack.push(1)<\/code> \u2192 [1]<\/li>\n      <li><code>stack.push(3)<\/code> \u2192 [1, 3]<\/li>\n      <li><code>stack.pop()<\/code> \u2192 returns 3 \u2192 [1]<\/li>\n      <li><code>stack.peek()<\/code> \u2192 returns 1<\/li>\n    <\/ul>\n\n    <h3>Examples<\/h3>\n    <ul>\n      <li>Stacks of Books<\/li>\n      <li>Undo\/Redo feature<\/li>\n      <li>Recursion (Function Call Stack)<\/li>\n      <li>Browsing History<\/li>\n    <\/ul>\n\n    <h2>What is a Queue?<\/h2>\n    <p><strong>Queue<\/strong> follows the <code>FIFO (First-In-First-Out)<\/code> principle. The first element added is the first to be removed.<\/p>\n\n    <h3>Queue Operations<\/h3>\n    <ul>\n      <li><strong>Enqueue:<\/strong> Add an element to the end<\/li>\n      <li><strong>Dequeue:<\/strong> Remove element from the front<\/li>\n      <li><strong>Peek\/Front:<\/strong> View the front-most element<\/li>\n    <\/ul>\n\n    <h2>Visualisation:<\/h2>\n    <img decoding=\"async\"\n        src=\"https:\/\/namastedev.com\/blog\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-05-at-12.46.57\u202fAM.png\"\n        alt=\"Queue\"\n    \/>\n        \n    <h3>Examples<\/h3>\n    <ul>\n      <li>Ticket Counter<\/li>\n      <li>OS Task Scheduling<\/li>\n      <li>Printers<\/li>\n      <li>Queues (in general)<\/li>\n    <\/ul>\n\n    <h2>Why Use Stack and Queue\u2753<\/h2>\n    <ul>\n      <li>Organize data logically (based on problem\u2019s need).<\/li>\n      <li>Order of Operations Matter<\/li>\n      <li>Optimize time &#038; memory for specific scenarios<\/li>\n    <\/ul>\n\n    <h3>Use Cases<\/h3>\n    <ul>\n      <li>Recursion (stack)<\/li>\n      <li>Level Order Traversal (queue)<\/li>\n      <li>BFS (queue)<\/li>\n      <li>DFS (stack)<\/li>\n    <\/ul>\n\n    <h2>Language Implementation<\/h2>\n\n    <h3>JavaScript<\/h3>\n    <pre><code class=\"language-js\">\nlet stack = [];\nstack.push(10);\nstack.push(7);\nstack.pop();    \/\/ returns 7\nstack.pop();    \/\/ returns 10\n    <\/code><\/pre>\n\n    <h3>Java<\/h3>\n    <pre><code class=\"language-java\">\nStack<Integer> stack = new Stack<>();\nstack.push(10);\nstack.pop();\nstack.peek();\n    <\/code><\/pre>\n\n    <h3>C++<\/h3>\n    <pre><code class=\"language-cpp\">\n#include &lt;stack&gt;\nstd::stack<int> s;\ns.push(10);\ns.pop();\ns.top();\n    <\/code><\/pre>\n\n    <h3>Python<\/h3>\n    <pre><code class=\"language-python\">\nstack = []\nstack.append(10)\nstack.pop()\ntop = stack[-1]  # peek\n    <\/code><\/pre>\n\n<p><strong>Note:<\/strong>Find out more about stacks in your preferred programming language.<\/p>\n    <h2>Stack vs Queue<\/h2>\n    <div class=\"search-comparison\">\n      <div class=\"comparison-card linear\">\n        <h3>\ud83d\udce5 Stack<\/h3>\n        <ul>\n          <li>Last-In-First-Out<\/li>\n          <li>Access only from top<\/li>\n          <li>Used in DFS, Recursion<\/li>\n        <\/ul>\n      <\/div>\n      <div class=\"comparison-card binary\">\n        <h3>\ud83d\udce4 Queue<\/h3>\n        <ul>\n          <li>First-In-First-Out<\/li>\n          <li>Access from front &#038; rear<\/li>\n          <li>Used in BFS, Scheduling<\/li>\n        <\/ul>\n      <\/div>\n    <\/div>\n\n    <h2>comparison with other Data-Structures<\/h2>\n<img decoding=\"async\"\n        src=\"https:\/\/namastedev.com\/blog\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-05-at-12.46.21\u202fAM.png\"\n        alt=\"table\"\n    \/>\n  <\/div>\n<\/div>\n\n<script>\ndocument.addEventListener(\"DOMContentLoaded\", () => {\n  const buttons = document.querySelectorAll(\".wp_blog_code-tab-button\");\n  const contents = document.querySelectorAll(\".wp_blog_code-tab-content\");\n\n  buttons.forEach((button) => {\n    button.addEventListener(\"click\", () => {\n      const lang = button.getAttribute(\"data-lang\");\n\n      buttons.forEach((btn) => btn.classList.remove(\"active\"));\n      contents.forEach((content) => content.classList.remove(\"active\"));\n\n      button.classList.add(\"active\");\n      document\n        .querySelector(`.wp_blog_code-tab-content[data-lang=\"${lang}\"]`)\n        .classList.add(\"active\");\n    });\n  });\n\n  const themeToggle = document.getElementById(\"blogNotesThemeToggle\");\n  const themeContainer = document.querySelector(\".wp_blog_theme\");\n\n  themeToggle.addEventListener(\"click\", () => {\n    themeContainer.classList.toggle(\"dark-mode\");\n    themeToggle.textContent =\n      themeContainer.classList.contains(\"dark-mode\") ? \"\u2600\ufe0f\" : \"\ud83c\udf19\";\n  });\n});\n<\/script>\n\n","protected":false},"excerpt":{"rendered":"<p>\ud83c\udf19 What is a Stack? Stack follows the LIFO (Last-In-First-Out) principle. The last element added is the first one to come out. Stack Operations Push: Add an element to the top Pop: Remove the top element Peek\/Top: View the top-most element Visualisation: Example Flow stack.push(1) \u2192 [1] stack.push(3) \u2192 [1, 3] stack.pop() \u2192 returns 3<\/p>\n","protected":false},"author":108,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[210,322,260,176,175,211,811,810,217,314,174,172,173,284],"tags":[],"class_list":{"0":"post-7558","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-algorithms","7":"category-algorithms-and-data-structures","8":"category-c-c-plus-plus","9":"category-csharp","10":"category-cplusplus","11":"category-data-structures","12":"category-data-structures-and-algorithms","13":"category-dsa","14":"category-interview-experience","15":"category-interview-preparation","16":"category-java","17":"category-javascript","18":"category-python","19":"category-software-engineering"},"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/posts\/7558","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/users\/108"}],"replies":[{"embeddable":true,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/comments?post=7558"}],"version-history":[{"count":4,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/posts\/7558\/revisions"}],"predecessor-version":[{"id":10203,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/posts\/7558\/revisions\/10203"}],"wp:attachment":[{"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/media?parent=7558"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/categories?post=7558"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/tags?post=7558"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}