pointer_in_c_programming_structure and uses.pptx

pointer_in_c_programming_structure and uses.pptx

• 1.
  POINTERS WITH FUNCTION
• 2.
  POINTERS Definition • variable thatstores the memory address of another variable. • directly refers to the location of a value in memory. Used for • dynamic memory allocation • efficient manipulation of data. • implementation of various advanced data structures and algorithms.
• 3.
  BASICS OF POINTERS •Syntax Data_type *pointer_variable_name; • Example: Declaration int *intPointer; Initialization int variable = 10; int *intPointer = &variable; • * -> Dereference operator.
• 4.
  POINTER ARITHMETIC • manipulatingthe memory addresses stored in pointers. • navigating through arrays, structures, and dynamic memory. Increment (`++`) and Decrement (`--`). • Example • int numbers[] = {10, 20, 30, 40, 50}; • int *ptr = numbers; // Points to the first element of the array • Pointer Increment: • ptr++; • Pointer Decrement • ptr--;
• 5.
  PASSING POINTERS TOFUNCTIONS • Syntax Return_type function_name(data_type *parameter_name) { //function body } • Example Void modifyValue(int *ptr) { *ptr = 20; } • Advantages efficient memory usage Direct Modification of Original Data Reduced Overhead Dynamic Memory Manipulation
• 6.
  RETURNING POINTERS FROMFUNCTIONS • Syntax Data_type* function_name() { // Allocate memory and return a pointer to it } • Example int* allocateAndReturn() { int *ptr = (int*)malloc(sizeof(int)); // Additional logic or data initialization if needed return ptr; }
• 7.
  DYNAMIC MEMORY ALLOCATION •Malloc (Memory Allocation) • It is used to dynamically allocate a specified number of bytes of memory. • Returns a pointer to the beginning of the allocated memory. Example: Allocating memory for an integer int *ptr = (int*)malloc(sizeof(int)); • Calloc (Contiguous Allocation) • contiguous memory allocation and initializes the allocated memory to zero. • Takes two arguments – the number of elements and the size of each element. • Returns a pointer to the beginning of the allocated memory. // Example: Allocating memory for an array of 5 integers int *arr = (int*)calloc(5, sizeof(int));
• 8.
  • Free • freeis used to deallocate memory previously allocated using malloc or calloc. • It takes a pointer to the memory block to be freed. • After freeing memory, the pointer should not be used until reallocated. // Example: Freeing dynamically allocated memory free(ptr);
• 9.
  ARRAYS AND POINTERS •Array Name as a Pointer: int numbers[] = {10, 20, 30}; int *ptr = numbers; // Equivalent to &numbers[0] • Pointer Arithmetic with Arrays & Array Indexing with Pointers: int firstElement = *ptr; // 10 int secondElement = *(ptr + 1); // 20 • Advantages Dynamic Array Sizes Efficient Function Arguments Flexibility in Memory Manipulation
• 10.
  FUNCTION POINTERS • Definition .Point to functions instead of data . Call functions indirectly through the pointer. • Declaration int (*functionPtr)(int, int); • Initialization int add(int a, int b) { return a + b; } int (*functionPtr)(int, int) = add;
• 11.
  REAL WORLD EXAMPLESOF POINTERS IN FUNCTIONS • Dynamic Memory Allocation malloc, calloc, and realloc return pointers to dynamically allocated memory. • String Manipulation strcpy, strcat, and strlen use pointers to manipulate strings efficiently. • Sorting Algorithms Quicksort or mergesort often use function pointers • Function Pointers in API Libraries: APIs often use function pointers to define plugin interfaces • Memory Management in Data Structures Data structures like linked lists, trees, and graphs often use function pointers
• 12.
  EXAMPLE PROGRAM #include <stdio.h> voidswap(int *a, int *b) { int temp = *a; *a = *b; *b = temp; } int main() { int x = 5, y = 10; printf(“Before swapping: x = %d, y = %dn”, x, y); swap(&x, &y); printf(“After swapping: x = %d, y = %dn”, x, y); return 0; }