📚 Topics to learn in C 👨‍🏫

Getting started with C Language
- The history of C.
- The evolution of the C programming standards.
- The relationship of C to C++.
- Some recommended / free books for learning C.
- Source Code Compilation, Cross-Compilation Process.
- C/C++ Toolchains and Open Source IDEs.
Compiling
- gcc = gcc C compiler
- gcc -o myprog hello.c create an executable output file called myprog and hello.c is input source code.
Code Comments
- Single-line comments: // ....
- Multple-line comments: /* ... */
- Keywords or reseverd words in C
Data Types
- Basic data types
  - 'int' represents integers (whole numbers) with varying sizes depending on the platform.
  - 'char' represents single characters.
  - 'float' represents single-precision floating-point numbers.
  - 'double' represents double-precision floating-point numbers.
  - 'bool' (via #include <stdbool.h>) represents boolean values ('true' or 'false').
  - '_Bool' (C99's boolean type)
  - 'unsigned char' declares a variable which can hold values from 0 to 255.
- Derived Data Types
  - Arrays, structures, unions
  - Enumerated data types (the 'enum' keyword)
- 'void' data type
  - a special data type that indicates the absence of a specific type.
  - used to represent a lack of value or to indicate that a function does not return any value.
Type Modifiers for Numbers
- integers: such as 'signed', 'unsigned', 'short', 'long', 'long long'
- floating-points: 'long' (for 'float' and 'double')
Type Conversions
- Implicit: short to int to long, float to double.
- Explicit: ()(expression) for type-casting.
Literals (constant values of specific data types)
- Primitive vs. Compound Literals
- Integer Literal: 42, -100, 0, 123456
- Octal Literal: 0644
- Hexadecimal Literal: 0x1A, 0xFF, 0xABC
- Floating-Point Literal: 3.14, -0.005, 1.0e-5
- Character Literal: 'A', '5', '!', '\n'
- Boolean Literal (C99 and later): true, false
- String Literal: "Hello, world!", "" (an empty string)
Identifiers and Variables
- Identifier Naming
- Variable Definition and Initialization
- Variable Scope
- Constants (with the const keyword)
- Declaration vs. Definition
- A declaration introduces an identifier to the compiler and informs it about the data type and name of the identifier.
- A definition creates the actual instance of an identifier in memory. It allocates memory for variables and provides the implementation for functions.
- Global & local variables
Operators
- Arithmetic Operators: +, -, *, /, %, ++, --
- Relational Operators: ==, !=, >, <,>=, <= - Logical Operators: &&, ||, !
- Bitwise Operators: &, |, ^, ~, <<,>>
- Assignment Operators: =, +=, -=, *=, /=, %=, &=, |=, ^=, >>=, <<=
- Conditional Operator: () ? () : ()
- Miscellaneous Operators:
  - , (comma), & (address-of operator)
  - sizeof(...) used to determine the size in bytes of a data type or variable.
  - . (dot or memory-access operator)
  - -> (memory-access operator),
  - [...] (square bracket or array indexing operator)
- Side Effects of the ++ and -- Operators for Value Modification
  - Pre-increment and Pre-decrement
  - Post-increment and Post-decrement
  - Order of Evaluation
- Short-circuit logical operators
  - The && (logical AND) operator: (expr1 && expr2)
  - The || (logical OR) operator: (expr1 || expr2)
  - These short-circuit operators halt evaluation once the final outcome is determined by the preceding sub-expressions.
Strings
- A string is a sequence of characters stored in an array that represents text.
- terminated by a null character ('\0').
- accessible by a (char *) pointer.
- string terminator = String in C always end with a byte set to 0
- mystring[] declaresd as as array often chars
String library
- Using the C string library to simplify common opearations on strings
- <string.h> : strcpy() , strcat() , strlen() , strcmp() , strncmp()
User input
- sscanf reads values from string
- scanf reads values directly from the console
- fgets 3 arguments : buffer store input : maximum number of byte : where to read from (stdin = read from the console)
Array: 1D and 2D
- llection of elements of the same data type, stored in contiguous memory locations.
- Relationship between pointers and arrays = Can use pointer to access the address in elements of the array.
- Elements in arrey use adjacent address
Structs (short for structures)
- a composite data type that allows you to group together variables of different data types under a single name.
Union
- a user-defined data type that all members of a union share the same memory location.
Bit-field
- a bit field is used to specify the number of bits to be used to store a particular data member within a struct.
Enumeration (enum)
- a user-defined data type that consists of a set of named integer constants.
Typedef for user-defined types
- used to create an alias or a new name for an existing data type.
- provides a way to define custom names for data types.
Statements such as
- Iteration Statements/Loops: for, while, do-while
- Selection Statements: if, if-else, switch-case
- Assignment Statements
- Leaving a loop early : break
Functions
- Variable arguments of a function
- Build and calling a function
- Returning the value of a function
Pointers
- Pointer Arithmetics
- Function Pointers and Parameters
- Name are pointers = The name of an array or a string is just a pointer to the frist element of the array or string.
Header files and the preprocessor
C Preprocessor Directives and Macros
- #include <...>: include header files.
- #define
- #if, #else, #ifdef, #ifndef, #endif, #undef
- #error
Command-line arguments to the main() function
- provided by the user when they run the program and can be used to pass information or parameters to the program.
- int main(int argc, char *argv[]) { ... }
The C Standard I/O library
- printf() and scanf() functions.
- fprintf() functions and the output streams ('stdout' and 'stderr').
- Formatted strings for Input/Output
Files and I/O streams
- <stdio.h> (Standard I/O Library) provides functions for basic input and output operations.
  - Examples of functions in this library:
  - fopen(), fclose()
  - fprintf(), fscanf()
  - fputc(), fgetc(), fgets(), fputs()
  - fwrite(), fread(), feof(), fseek(), rewind()
  - file access mode : rb+ , wb+ , ab+
- Other standard C libraries:
  - <stdlib.h> provides functions for various file operations.
  - <unistd.h> (Unix Standard Library) provides functions for low-level file operations.
  - <sys/types.h> and <sys/stat.h> provide data types and functions for working with file status and attributes.
  - <fcntl.h> provides functions for managing file descriptors and controlling file attributes.
Pseudo-Random Number Generation
- srand(): used to seed the random number generator.
- rand(): returns an integer between 0 and RAND_MAX.
- Both functions are declared in <stdlib.h>
The C Standard Math library
- The <math.h> header file must be included in source code in order to use the C Standard Math library.
- The -lm flag must be specified for program linking (when using GCC C compiler).
POSIX Threads and Multithreading
- often referred to as pthreads.
- a standardized threading library for creating and managing threads in a multi-threaded program.

Baic GTK

What is GTK
- Muli-platform toolkit for GUI
GTK Version
- GTK 2 Stable
- GTK 3 Under development more features
Header file #include<gtk/gtk.h>
Basic Command
- gtk_init(&argc,&argv)
- gtk_window_new()
- gtk_widget_show(win)
- gtk_main()
Button and More
- gtk_button_new_with_label(label)
- gtk_container_add(GTK_CONTAINER(win),btn)
- gtk_widget_show_all(win)
- gtk_label_set_text(GTK_LABEL(ptr),buffer)
- gtk_table_attach_default(GTK_TABLE(tbl),lbl)
- g_signal_connect_(chk,"toggled",G_CALLBACK(check_toggle),NULL)

List stores

Text combo boxes

GtkWidget *comb = gtk_combo_box_text_new (); // new empty combo box
gtk_combo_box_text_append_text (GTK_COMBO_BOX_TEXT (comb), "Option 1");
gtk_combo_box_text_append_text (GTK_COMBO_BOX_TEXT (comb), "Option 2");
gtk_combo_box_text_append_text (GTK_COMBO_BOX_TEXT (comb), "Option 3");
gtk_combo_box_set_active (GTK_COMBO_BOX (comb), 0);

int sel = gtk_combo_box_get_active (GTK_COMBO_BOX (comb)); // Read currently selected item

Combo Callback

void combo_changed (GtkWidget *wid, gpointer ptr)
{
    int sel = gtk_combo_box_get_active (GTK_COMBO_BOX (wid));
    char *selected = gtk_combo_box_text_get_active_text (
    GTK_COMBO_BOX_TEXT (wid));
    printf ("The value of the combo is %d %s\n", sel, selected);
}
 g_signal_connect (comb, "changed", G_CALLBACK (combo_changed), NULL);

Menus

Menu bars
- GtkWidget *mbar = gtk_menu_bar_new ()

Pop-up Menus

//Handler to connect it to the clicked signal on a button.
void button_popup (GtkWidget *wid, gpointer ptr)
{
    GtkWidget *f_menu = gtk_menu_new ();
    GtkWidget *quit_mi = gtk_menu_item_new_with_label ("Quit");
    gtk_menu_shell_append (GTK_MENU_SHELL (f_menu), quit_mi);
    g_signal_connect (quit_mi, "activate", G_CALLBACK (end_program),
    NULL);
    gtk_widget_show_all (f_menu);
    gtk_menu_popup (GTK_MENU (f_menu), NULL, NULL, NULL, NULL, 1,
    gtk_get_current_event_time ());
}

Dialogs

// This can be connected to `clicked` signal with g_signal_connect
void open_dialog (GtkWidget *wid, gpointer ptr)
{
    GtkWidget *dlg = gtk_dialog_new_with_buttons ("My dialog",
    GTK_WINDOW (ptr),
    GTK_DIALOG_MODAL | GTK_DIALOG_DESTROY_WITH_PARENT,
    "Cancel", 0, "OK", 1, NULL);
    int result = gtk_dialog_run (GTK_DIALOG (dlg));
    gtk_widget_destroy (dlg);
    printf ("Return code = %d\n");
}

Review

Pro
- Color coded code easy to read
- Easy to understand language
- Clear Explaination
Cons
- No online Repositry
- No Code + Result Summary

Bipoeman/md_dump

📚 Topics to learn in C 👨‍🏫

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