Learn C

C Tutorial Introduction

• C is a general-purpose programming language designed for system and application programming.
• It is widely used for developing firmware and portable applications.
• Understanding C lays a strong foundation for learning other programming languages like C++, Java, and Python.

Downloading VS Code IDE

1. Visit the official Visual Studio Code website.
2. Download the installer for your operating system (Windows, macOS, or Linux).
3. Run the installer and follow the setup wizard instructions.

Creating a New Project in VS Code

1. Open VS Code.
2. Create a new folder for your project.
3. Go to File > Open Folder and select your project folder.
4. Use the Explorer tab to manage files and create new ones.

Installing Compiler

• C requires a compiler to translate the code into machine language.
• Install GCC (GNU Compiler Collection):
  • Windows: Install MinGW or TDM-GCC.
  • macOS: Use xcode-select --install to install GCC.
  • Linux: Use sudo apt install gcc.

Extensions in VS Code

• Install useful extensions:
  • C/C++ by Microsoft: Provides IntelliSense, debugging, and code browsing.
  • Code Runner: Enables running code snippets directly in the editor.

Creating the First C Program

1. In the project folder, create a new file: hello.c.

2. Write your first C program:

   #include <stdio.h>
   int main() {
       printf("Hello, World!\n");
       return 0;
   }

Configuring VS Code Settings

• Configure the compiler and terminal:
  1. Go to File > Preferences > Settings.
  2. Set the path for the GCC compiler in the environment variable or tasks.json.

Running Your First Program

1. Open the terminal in VS Code.

2. Compile the program:

   gcc hello.c -o hello
   

3. Run the executable:

   ./hello
   

Understanding Our First C Program

• #include <stdio.h>: Includes the standard I/O library for functions like printf.
• int main(): Entry point of the program.
• printf("Hello, World!\n");: Prints text to the console.
• return 0;: Indicates successful execution.

Creating Another C Program

• Create a file: sum.c.

• Write a program to add two numbers:

  #include <stdio.h>
  int main() {
      int a = 5, b = 10;
      printf("Sum: %d\n", a + b);
      return 0;
  }

Comments

• Single-line: // This is a comment

• Multi-line:

  /* This is 
     a multi-line comment */

Data Types

• Basic: int, float, char, double.
• Derived: array, pointer, structure.
• Enumeration: enum.

Variables

• Containers for storing data values.

• Example:

  int age = 25;
  float pi = 3.14;

sizeof() Function

• Returns the memory size of a data type or variable.

• Example:

  printf("Size of int: %lu\n", sizeof(int));

Rules for Defining Variables

1. Names must begin with a letter or underscore.
2. Case-sensitive.
3. Cannot use reserved keywords.

const Keyword

• Declares variables as read-only.

• Example:

  const float pi = 3.14159;

Operators

• Arithmetic: +, -, *, /, %.
• Relational: >, <, ==.
• Logical: &&, ||, !.

Taking User Input

• Example using scanf:

  int age;
  printf("Enter your age: ");
  scanf("%d", &age);

Typecasting

• Converts one data type to another.

• Example:

  float x = 5.7;
  int y = (int)x;

Decision-Making (Conditional Statements)

• if, else, else if:

  if (age > 18) {
      printf("Adult");
  } else {
      printf("Minor");
  }

Switch Case Statements

• Example:

  int day = 3;
  switch (day) {
      case 1: printf("Monday"); break;
      case 2: printf("Tuesday"); break;
      default: printf("Other day");
  }

Loops (Iterative Statements)

1. for loop:

   for (int i = 0; i < 10; i++) {
       printf("%d\n", i);
   }

2. while loop:

   int i = 0;
   while (i < 10) {
       printf("%d\n", i);
       i++;
   }

3. do-while loop:

   int i = 0;
   do {
       printf("%d\n", i);
       i++;
   } while (i < 10);

Functions

• Breaks the program into reusable parts.

• Example:

  int add(int a, int b) {
      return a + b;
  }

Arrays

• Stores multiple values of the same type.

• Example:

  int arr[5] = {1, 2, 3, 4, 5};

Pointers

• Variables that store the memory address of another variable.

• Example:

  int a = 10;
  int *ptr = &a;

Strings

• Array of characters ending with a null terminator (\0).

• Example:

  char name[] = "John";
  printf("Name: %s", name);

Structure

• User-defined data type to group variables.

• Example:

  struct Person {
      char name[50];
      int age;
  };