惯性聚合 高效追踪和阅读你感兴趣的博客、新闻、科技资讯
阅读原文 在惯性聚合中打开

推荐订阅源

让小产品的独立变现更简单 - ezindie.com
让小产品的独立变现更简单 - ezindie.com
美团技术团队
OSCHINA 社区最新新闻
OSCHINA 社区最新新闻
月光博客
月光博客
J
Java Code Geeks
Jina AI
Jina AI
罗磊的独立博客
宝玉的分享
宝玉的分享
S
SegmentFault 最新的问题
D
DataBreaches.Net
博客园 - 叶小钗
腾讯CDC
freeCodeCamp Programming Tutorials: Python, JavaScript, Git & More
Last Week in AI
Last Week in AI
钛媒体:引领未来商业与生活新知
钛媒体:引领未来商业与生活新知
Google DeepMind News
Google DeepMind News
阮一峰的网络日志
阮一峰的网络日志
B
Blog
V
Visual Studio Blog
雷峰网
雷峰网
博客园 - 【当耐特】
Apple Machine Learning Research
Apple Machine Learning Research
Engineering at Meta
Engineering at Meta
奇客Solidot–传递最新科技情报
奇客Solidot–传递最新科技情报

DEV Community

Authentication Security Deep Dive: From Brute Force to Salted Hashing (With Java Examples) Why AI Systems Don’t Fail — They Drift Spilling beans for how i learn for exam😁"Reinforcement Learning Cheat Sheet" I Replaced Chrome with Safari for AI Browser Automation. Here's What Broke (and What Finally Worked) How Python Borrows Other People's Work The $40 Architecture: Processing 1 Billion API Requests with 99.99% Uptime Vibe Coding: A Workflow Guide (From Zero to SaaS) Most webhook security guides protect the wrong side. The scary part is delivery. Headless CMS for TanStack Start: Build a Blog with Cosmic EU Age Verification App "Hacked in 2 Minutes" — What Actually Happened Comfy Cloud’s delete function does not actually remove files Running AI Models on GPU Cloud Servers: A Beginner Guide Event-driven media intelligence with AWS Step Functions and Bedrock I scored 500 AI prompts across 8 quality dimensions — here's what broke How to Call Google Gemini API from Next.js (Free Tier, No Backend Needed) The Portal Protocol: Reclaiming Human Connection in the Age of AI How to Fix Your Team's Scattered Knowledge Problem With a Self-Hosted Forum Intro to tc Cloud Functors: A Graph-First Mental Model for the Modern Cloud Designing Multi-Tenant Backends With Both Ownership and Team Access I Built a Neumorphic CSS Library with 77+ Components — Here's What I Learned PostgreSQL Performance Optimization: Why Connection Pooling Is Critical at Scale Cómo construí un SaaS multi-rubro para gestionar expensas en Argentina con FastAPI + Vue 3 🚀 I Built an Ethical Hacking Scanner Tool – Open Source Project I Replaced /usage and /context in Claude Code With a Single Statusline A Pythonic Way to Handle Emails (IMAP/SMTP) with Auto-Discovery and AI-Ready Design I Collected 8.9 Million Polymarket Price Points — Here's What I Found About How Markets Really Move EcoTrack AI — Carbon Footprint Tracker & Dashboard Everyone's Using AI. No One Agrees How. 5 self-hosted ebook managers worth trying in 2026 Building Your First AI Agent with LangChain: From Chatbot to Autonomous Assistant
🕵️‍♂️ How Computers "Hide" a Minus Sign: The 2's Compleme...
Laiba · 2026-04-27 · via DEV Community

Laiba

Ever wondered how a computer stores a negative number? It doesn't have a tiny "minus" symbol inside the hardware. 🤖

Instead, it uses a clever mathematical ritual called Two’s Complement.

The "Flip and Add" Recipe 🍳

If you want to store -5 in an 8-bit char, the computer doesn't just put a sign in front. It follows these three steps:

  1. Start with the Positive: Write 5 in binary $\rightarrow$ 00000101
  2. Flip the Bits: Change every 0 to 1 and every 1 to 0 $\rightarrow$ 11111010
  3. Add 1: Add a binary 1 to that result $\rightarrow$ 11111011

Boom! That’s exactly how -5 sits in your memory.


Why do we do this? (The Genius Part) 🧠

Why not just change the first bit to 1 and call it a day?

Because with Two's Complement, addition and subtraction work perfectly without any extra "brain power" from the CPU. When you add 5 (00000101) and -5 (11111011), the bits naturally add up to 0 (after a small overflow).

It turns subtraction into simple addition! ➕


⚠️ The "Unsigned" Trap

This is the part Love Babbar often emphasizes: If you use an unsigned variable, you are telling the computer: "Ignore the minus sign glasses!" 👓

If you store -5 in an unsigned variable, the computer sees that leading 1 and thinks it's a massive number (like 4 billion) instead of a negative sign.

Key Lesson: Bits are just bits. It’s the Data Type that tells the computer how to read them!


🙌 Shoutout

Huge thanks to Love Babbar for the "Code Help"! 🚀 His explanation of how memory actually interprets these bits is a game-changer for understanding C++ foundations.

What concept should I dive into next? DBMS or more C++ quirks? 👇