CS50 Fall 2025 - Lecture 1 - C (live, unedited) | CS50

In this lecture, the speaker transitions the audience from Scratch to C programming, emphasizing that the underlying logic remains consistent despite syntax changes. The session covers source code, machine code, and the role of compilers, introducing the VS Code environment and basic C syntax. It further explains functions, arguments, and side effects, alongside essential C elements such as conditionals, loops, operators, and data types. The lecture also touches on debugging, common errors, and resources like CS50's manual pages. It concludes with practical examples, including creating a basic calculator and addressing limitations like integer overflows and floating-point precision, setting the stage for upcoming problem sets.

Outlines

Part 1: Introduction, Environment

Part 2: Syntax, Input, Linux Commands

Part 3: Data Types, Conditionals, Loops

Part 4: Functions, Design, Style

Part 5: Advanced Logic, Practical Examples

Part 6: Limitations, Future Outlook

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CS50 Fall 2025 - Lecture 1 - C (live, unedited)

CS50

Part 1: Introduction, Environment

Introduction to C and the CS50 Development Environment

Compiling and Running a Simple C Program

Part 2: Syntax, Input, Linux Commands

Understanding C Syntax and Escape Sequences

CS50 Library and User Input with GetString

Modifying the Hello Program and Introducing Linux Commands

Demonstrating Linux Commands in VS Code

Part 3: Data Types, Conditionals, Loops

Conditionals, Operators, and Data Types in C

CS50's Get Functions and Implementing Conditionals

Flowcharts and Loop Structures in C

Infinite Loops and User Input Validation

Part 4: Functions, Design, Style

Creating Custom Functions in C

Implementing a Dynamic Meow Program and Introducing Style Guidelines

Part 5: Advanced Logic, Practical Examples

Implementing a Mario Program with Nested Loops

Implementing a Calculator Program and Exploring Integer Overflow

Part 6: Limitations, Future Outlook

Floating Point Precision and the Year 2038 Problem

CS50 Fall 2025 - Lecture 1 - C (live, unedited)

CS50

Part 1: Introduction, Environment

17:47Introduction to C and the CS50 Development Environment

Introduction to C and the CS50 Development Environment

26:02Compiling and Running a Simple C Program

Compiling and Running a Simple C Program

Part 2: Syntax, Input, Linux Commands

34:12Understanding C Syntax and Escape Sequences

Understanding C Syntax and Escape Sequences

47:01CS50 Library and User Input with GetString

CS50 Library and User Input with GetString

52:23Modifying the Hello Program and Introducing Linux Commands

Modifying the Hello Program and Introducing Linux Commands

1:02:35Demonstrating Linux Commands in VS Code

Demonstrating Linux Commands in VS Code

Part 3: Data Types, Conditionals, Loops

1:13:03Conditionals, Operators, and Data Types in C

Conditionals, Operators, and Data Types in C

1:20:23CS50's Get Functions and Implementing Conditionals

CS50's Get Functions and Implementing Conditionals

1:30:33Flowcharts and Loop Structures in C

Flowcharts and Loop Structures in C

1:41:13Infinite Loops and User Input Validation

Infinite Loops and User Input Validation

Part 4: Functions, Design, Style

1:52:23Creating Custom Functions in C

Creating Custom Functions in C

2:04:36Implementing a Dynamic Meow Program and Introducing Style Guidelines

Implementing a Dynamic Meow Program and Introducing Style Guidelines

Part 5: Advanced Logic, Practical Examples

2:18:42Implementing a Mario Program with Nested Loops

Implementing a Mario Program with Nested Loops

2:33:24Implementing a Calculator Program and Exploring Integer Overflow

Implementing a Calculator Program and Exploring Integer Overflow

Part 6: Limitations, Future Outlook

2:47:28Floating Point Precision and the Year 2038 Problem

Floating Point Precision and the Year 2038 Problem