▶ Coding Reality
- Most developers debug by re-running code without understanding it.
- You can earn well in software while treating computers like magic.
▶ What a Computer Is
- A computer is essentially a Turing Machine.
- Built from billions of transistors acting as ON/OFF switches.
- Smallest unit: Bit (0 or 1)
- 8 bits = 1 Byte (256 values)
- Characters mapped using ASCII / UTF-8.
▶ Binary & Machine Code
- Computers use binary (base-2).
- Humans prefer hexadecimal (base-16).
- Code is converted into machine code for the CPU.
▶ Memory & Hardware
- RAM stores data using memory addresses.
- CPU + RAM = the brain of the computer.
- Input devices (keyboard, mouse), Output devices (monitor).
- OS (Linux, Windows, macOS) manages hardware via drivers.
- Shell = interface to interact with OS (CLI, SSH).
▶ Programming Languages
- Interpreted: Python (line-by-line execution).
- Compiled: C/C++ (compiled to executable).
- Abstraction hides hardware complexity.
▶ Variables & Memory
- Variable names and data are stored in memory.
- Dynamic typing (Python) vs Static typing (C).
- Pointers store memory addresses.
- The garbage collector manages memory automatically.
▶ Data Types
- int, float, double for numbers.
- char, string for text.
- Big-endian vs Little-endian memory storage.
▶ Data Structures
- Array/List: indexed, ordered.
- Linked List: nodes with pointers.
- Stack: LIFO
- Queue: FIFO
- Hash Map / Dictionary: key–value pairs.
- Tree: hierarchical structure.
- Graph: nodes + edges (relationships).
▶ Algorithms
- Algorithms solve problems using data structures.
- Functions take input → process → return output.
- Expressions produce values; Statements perform actions.
- Conditionals (if/else), Loops (for/while).
- Recursion uses a call stack → risk of stack overflow.
- Base condition prevents infinite recursion.
▶ Performance Analysis
- Big-O notation measures efficiency.
- Time complexity & Space complexity.
▶ Algorithm Types
- Brute Force
- Divide & Conquer (Binary Search)
- Dynamic Programming (Memoization)
- Greedy Algorithms (e.g., Dijkstra)
- Backtracking (exploring all paths)
▶ Programming Paradigms
- Declarative (what to do)
- Imperative (how to do)
- Functional, Procedural
- Object-Oriented Programming (Classes & Objects)
- Inheritance & Design Patterns
▶ Memory Areas
- Stack: short-lived function calls.
- Heap: long-lived objects, passed by reference.
▶ Concurrency & Parallelism
- Threads enable parallel execution.
- Concurrency via event loops & coroutines.
▶ Networking & Cloud
- Virtual Machines simulate hardware.
- IP addresses identify machines.
- DNS maps URLs to IPs.
- TCP handshake establishes a connection.
- SSL encrypts data.
- HTTP transfers web data.
- APIs (REST) expose server data.
▶ Final Truth
- You must learn printers.
- Because grandma will ask you to fix them.
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