My C, Kernel study legacy from 42Seoul

This repository contains a collection of C programming practice scripts, inspired by the 42 La Piscine curriculum. Each file demonstrates a specific C language concept or system programming technique, ranging from basic input/output to more advanced topics like string manipulation, control flow, and operator precedence.

What You'll Find Here

• Input/Output: Reading and formatting user input, printing results (scanf, printf).
• Arithmetic & Operators: Integer and floating-point arithmetic, modular arithmetic, relational and logical operators, operator precedence.
• Control Flow: Conditional statements (if, else if, else, switch), loops.
• String Handling: Character arrays, string functions (strlen, strncmp), string formatting.
• Bitwise and Boolean Logic: Exploring how C handles boolean expressions and bitwise operations.
• Pointers: Pointer declaration, assignment, dereferencing, pointer arithmetic, and function arguments.
• Structures: Defining and using structs to group data.
• System/Kernel Concepts: (If any files cover system calls, memory management, or kernel-level operations, they will be listed here.)

File Overview

• upc.c, upc-one-digit.c: Practice with formatted input and check digit calculation.
• windspeed.c: Categorizing wind speeds using conditional logic.
• string-prac.c: String comparison and manipulation.
• section_4_2.c, section_4_2_9.c, section_4_3_11.c: Operator precedence, boolean logic, and arithmetic.
• score-if.c: Grading logic with nested if-else.
• scanf-int-float-seq.c, scanf-int-float-seq2.c: Mixed input types and order.
• space-distinguish.c: Handling input with spaces and delimiters.
• product-info-enter.c: Structured input and formatted output.
• tel_area_code.c: Using switch for mapping codes to names.
• several-int-float.c, several-int-float2.c: Variable declaration and output.
• single-expression.c: Ternary operator and expression evaluation.
• stars.c: Output formatting for patterns.
• three-digits-reverse.c: Integer manipulation and digit extraction.
• two-digits-english.c: Mapping numbers to English words.
• time24-to-12.c: Time conversion and formatted output.

io/

• date-display.c: Reading and displaying a date in a different format. (Input/output, scanf/printf formatting)

pointer/

• more-pointer.c: Swapping two integers using pointers. (Pointers, function arguments, dereferencing)
• pointing-to-same-address.c: Printing the address of a variable. (Address-of operator, pointers)
• address-void.c: Using pointers and dereferencing (undefined behavior example). (Pointers, uninitialized pointers)
• array-pointer.c: Array and pointer relationships in C. (Arrays, pointers, pointer arithmetic)
• address-print.c: Assigning and dereferencing pointers. (Pointers, address-of, dereferencing)
• address-print2.c: Pointer assignment, dereferencing, and memory addresses. (Pointers, address-of, memory addresses)

pointer/create-pointer/

• create-pointer.c: Creating and assigning pointers. (Pointer assignment, address-of operator)

structure/

• example.c: Using structures to store and print data. (Struct definition, member access)

sum/

• add-two-numbs.c: Adding two numbers input by the user. (Integer input, arithmetic)

How I Studied and Practiced

I practiced C programming by writing small, focused programs for each concept. For each topic, I:

• Wrote a minimal program to demonstrate the concept.
• Compiled and ran the program to observe its behavior.
• Experimented with variations and edge cases.
• Added comments to explain the purpose and key concepts in each file.

This hands-on approach helped me build a strong foundation in C, covering input/output, arithmetic, control flow, pointers, structures, and more.

How to Use

Each .c file is standalone and can be compiled with gcc:

gcc filename.c -o filename
./filename

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This repository is a great resource for anyone looking to strengthen their understanding of C programming fundamentals, operator behavior, and input/output handling. Each file is commented to explain its purpose and the concepts it demonstrates.