Module 10: Pointers & Deep Memory Mastery

1. Interactive Simulator 1 / 4

Interactive Pointer & Memory Address Simulator

Understanding & (address-of) and * (dereference) operators

${Visualizers.renderPointerPlayground()}

2. Pointer Arithmetic 2 / 4

Pointer Arithmetic & Byte Scaling

Why ptr + 1 advances by sizeof(*ptr) bytes

When you add 1 to a pointer, the CPU advances the address by the size of the underlying data type:

pointer_arithmetic.c

int numbers[3] = {100, 200, 300};
int *ptr = numbers; // Address: 0x1000

// ptr + 1 advances by 4 bytes (sizeof(int)) -> Address: 0x1004!
printf("Value: %d\\n", *(ptr + 1)); // Prints 200

double d_arr[2] = {1.1, 2.2};
double *d_ptr = d_arr; // Address: 0x2000
// d_ptr + 1 advances by 8 bytes (sizeof(double)) -> Address: 0x2008!

3. Double Pointers 3 / 4

Double Pointers (int **ptr) & Modifying Pointers in Functions

Pointer to a Pointer architecture

If you want a function to modify where a pointer points (e.g. allocating memory inside a helper function or linked list head insertion), you must pass a pointer to that pointer:

double_pointer.c

void allocate_buffer(int **ptr_address, size_t size) {
    *ptr_address = malloc(size * sizeof(int));
}

int main(void) {
    int *my_array = NULL;
    allocate_buffer(&my_array, 100);
    // my_array now successfully points to the 100-integer heap block!
    free(my_array);
    return 0;
}

4. Function Pointers 4 / 4

Function Pointers & Dynamic Dispatch Tables

Passing behavior dynamically in C

function_pointer.c

// Typedef signature: int (*Operation)(int, int)
typedef int (*BinOp)(int, int);

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

void execute(int x, int y, BinOp op) {
    printf("Result: %d\\n", op(x, y));
}

Pointer Concept	Syntax	Meaning
Null Pointer	`NULL`	Points nowhere (0x0). Safe check before dereferencing.
Wild Pointer	`int *p;`	Uninitialized pointer holding random garbage memory address.
Dangling Pointer	`free(p);`	Points to memory that has already been deallocated.
Generic Pointer	`void *p;`	Holds raw address of any type; must be cast before dereference.

Module 10: Pointers & Deep Memory Mastery

Interactive Pointer & Memory Address Simulator

Pointer Arithmetic & Byte Scaling

Double Pointers (int **ptr) & Modifying Pointers in Functions

Function Pointers & Dynamic Dispatch Tables

1. Pointer Types Summary

2. Practice Exercises & Solutions