Tags: #◇Computer Science #◇CCPROG2 #◇C Programming #◇Pointers #◇Reviewer #◇Finals

CCPROG2 Comprehensive Finals Reviewer

◇Overview

This reviewer consolidates Advanced C Programming (CCPROG2). Core topics include pointer arithmetic and dereferencing, multi-dimensional arrays, strings and string library functions, user-defined structures and unions, dynamic memory allocation (malloc, calloc, realloc, free), file handling (fopen, fread, fwrite, fprintf, fscanf), and recursion.

◇1. Pointers & Memory Architecture

Pointer Operators & Equivalences

Address-of &x: Returns the physical memory address of variable x.
Dereference *p: Accesses the value stored at memory address stored in p.
Array-Pointer Identity: For array arr, arr[i] \equiv *(arr + i) \equiv *(i + arr) \equiv i[arr].
Pointer Arithmetic: If p is T*, p + 1 increments address by sizeof(T) bytes!

◇2. Dynamic Memory Management Functions

Function Prototype	Description	Return on Failure
`void* malloc(size_t size);`	Allocates uninitialized heap memory of `size` bytes.	`NULL`
`void* calloc(size_t num, size_t size);`	Allocates and zero-initializes `num * size` bytes.	`NULL`
`void* realloc(void *ptr, size_t new_size);`	Resizes an allocated block; preserves existing content.	`NULL` (original block remains valid)
`void free(void *ptr);`	Releases allocated heap memory back to the OS.	`void` (Passing `NULL` is a safe no-op)

[!WARNING] Common Memory Vulnerabilities

Dangling Pointer: A pointer that points to deallocated memory after free(p). (Fix: free(p); p = NULL;).

Memory Leak: Allocated memory on heap lost when all pointers to it go out of scope without calling free().

Double Free: Calling free() twice on the same pointer causes heap corruption / crashes.

◇3. Structures & File I/O Summary

Structure Access

Given struct Student s; $\to$ Dot operator: s.id.
Given struct Student *p = &s; $\to$ Arrow operator: p->id (equivalent to (*p).id).

File Streams

Opening: FILE *fp = fopen("data.bin", "rb"); (Modes: "r", "w", "a", "rb", "wb"). Always check if (fp == NULL).
Text I/O: fprintf(fp, ...), fscanf(fp, ...), fgets(buffer, size, fp).
Binary I/O:
- size_t fwrite(const void *ptr, size_t size, size_t count, FILE *stream);
- size_t fread(void *ptr, size_t size, size_t count, FILE *stream);
Closing: fclose(fp); flushes buffers and releases file descriptor.

◇4. High-Yield Exam Checklist

Does realloc overwrite the original pointer immediately? Check if void *temp = realloc(...) to prevent leak on failure!
In char str[] = "Hello";, what is sizeof(str)? $6$ bytes (includes null terminator \0).
What is strlen("Hello")? $5$ (excludes \0).
In struct, does member ordering affect memory footprint? YES (Structure padding and alignment).
Did you check feof(fp) before or after reading? Check after read operation!

Previous Topic: ◇CCPROG1
Next Topic: ◇CCDSALG, ◇CCPROG3
Prerequisites: ◇Advanced C, Pointers, Dynamic Memory, Structs
Cross-Curricular Connections: ◇CSOPESY

[REV] CCPROG2 COMPREHENSIVE FINALS REVIEWER