C Programming

C Programming Study Notes

File Input and Output

• File Operations:
  • Opening a file: fopen()
  • Closing a file: fclose()
  • Reading from a file: fscanf(), fgets(), fgetc()
  • Writing to a file: fprintf(), fputs(), fputc()
• File Modes:
  • "r": Read
  • "w": Write (truncate)
  • "a": Append
  • "rb", "wb", "ab": Binary mode
• Error Handling:
  • Check if the file pointer is NULL to handle errors.

Pointers and Memory Management

• Pointers:
  • Variable that stores the memory address of another variable.
  • Syntax: type *pointerName;
  • Dereferencing: *pointer to access the value at the address.
• Dynamic Memory Allocation:
  • malloc(size): Allocates memory.
  • calloc(num, size): Allocates and initializes memory.
  • realloc(pointer, newSize): Resizes allocated memory.
  • free(pointer): Deallocates memory to prevent leaks.

Syntax and Data Types

• Basic Syntax:
  • Case-sensitive.
  • Statements end with a semicolon ;.
• Data Types:
  • Basic Types: int, float, double, char
  • Derived Types: array, pointer, structure, union
  • Enumeration: enum for defining a set of named integer constants.

Functions and Recursion

• Function Definition:
  • Syntax: returnType functionName(parameterList) { // body }
  • Supports function arguments and return values.
• Recursion:
  • Function calling itself.
  • Must have a base case to terminate.
  • Example: Factorial function.

Control Structures

• Decision Making:
  • if, if-else, switch for branching logic.
• Loops:
  • for, while, do-while for iteration.
  • break and continue for controlling loop execution.

Data Type

• Primitive Types:
  • int: Integer values.
  • char: Single character (1 byte).
  • float: Single precision floating-point.
  • double: Double precision floating-point.
• Size: Use sizeof() to determine the size of data types.

Arrays

• Definition: Collection of elements of the same type.
• Syntax: type arrayName[size];
• Accessing Elements: Using index notation arrayName[index].
• Multi-Dimensional Arrays: Defined as type arrayName[size1][size2];.

Structures

• Definition: Custom data type to group different types.
• Syntax:
  • Define: struct StructureName { type member1; type member2; };
  • Create instances: struct StructureName varName;
• Access Members: Using dot operator varName.member1.

These notes cover fundamental concepts in C programming, focusing on essential aspects necessary for understanding and application.

File Input and Output

• File Operations: Utilize functions to manage file access: fopen() to open, fclose() to close, fscanf() and fgets() for reading data, and fprintf() and fputs() for writing.
• File Modes:
  • Use "r" for reading, "w" for writing (which truncates the file), "a" for appending data, and "rb", "wb", "ab" for binary modes.
• Error Handling: Always check if a file pointer is NULL to ensure successful file operations and manage potential errors.

Pointers and Memory Management

• Pointers: Variables that hold addresses of other variables. Defined using type *pointerName; and accessed through dereferencing with *pointer.
• Dynamic Memory Allocation:
  • malloc(size) allocates a specific size of memory.
  • calloc(num, size) allocates memory and initializes it to zero.
  • realloc(pointer, newSize) modifies the size of allocated memory.
  • free(pointer) releases allocated memory to avoid memory leaks.

Syntax and Data Types

• Basic Syntax: C is case-sensitive and requires statements to end with a semicolon ;.
• Data Types:
  • Basic Types include int (integer), float (single precision), double (double precision), and char (character).
  • Derived Types consist of arrays, pointers, structures, and unions.
  • Enumeration allows defining a collection of named integer constants using enum.

Functions and Recursion

• Function Definition: Structure a function with returnType functionName(parameterList) { // body }, enabling the passing of arguments and returning values.
• Recursion: Functions can call themselves. Effective recursion requires a base case to terminate, like a factorial function example.

Control Structures

• Decision Making: Implement branching logic using if, if-else, and switch statements.
• Loops: Enable repetitive execution with for, while, and do-while loops, using break to exit and continue to skip an iteration.

Data Type

• Primitive Types:
  • int represents integers.
  • char denotes a single character and occupies 1 byte.
  • float and double correspond to single and double precision floating-point numbers, respectively.
• Size Determination: Utilize the sizeof() operator to ascertain the memory size of different data types.

Arrays

• Definition: Arrays store a collection of elements of the same type, declared with type arrayName[size];.
• Accessing Elements: Elements in an array can be accessed using index notation arrayName[index].
• Multi-Dimensional Arrays: Declared as type arrayName[size1][size2]; to accommodate more complex data structures.

Structures

• Definition: Structures define custom data types to encapsulate various data types.
• Syntax:
  • Structure creation: struct StructureName { type member1; type member2; };
  • Instance creation: struct StructureName varName;
• Access Members: Access members of a structure using the dot operator, e.g., varName.member1.

This quiz covers essential topics in C programming related to file input/output operations and memory management through pointers. Test your knowledge on file operations like opening, closing, reading, and writing files, along with dynamic memory allocation techniques. Prepare for mastering these crucial aspects of C programming!