👀 Views: 828 💬 Answers: 1 📅 Created: 2025-06-12

c memory-management structs dynamic-allocation C

I'm encountering a serious issue with memory corruption that occurs when I'm using nested structs along with dynamic memory allocation in my C program. I have two structs: a `Person` struct that contains a dynamically allocated array of `Hobby` structs. After initializing and populating the `Person` struct, I start noticing that some of the data in the `Hobby` array gets corrupted under certain conditions. Here's a simplified version of my code: ```c #include <stdio.h>\n#include <stdlib.h>\n#include <string.h>\n typedef struct {\n char name[30];\n} Hobby;\n typedef struct {\n char name[30];\n int age;\n Hobby* hobbies;\n int hobby_count;\n} Person;\n Person* create_person(const char* name, int age, int hobby_count) {\n Person* p = malloc(sizeof(Person));\n if (!p) return NULL;\n strncpy(p->name, name, sizeof(p->name));\n p->age = age;\n p->hobby_count = hobby_count;\n p->hobbies = malloc(hobby_count * sizeof(Hobby));\n return p;\n}\n void add_hobby(Person* p, int index, const char* hobby_name) {\n if (index < p->hobby_count) {\n strncpy(p->hobbies[index].name, hobby_name, sizeof(p->hobbies[index].name));\n }\n}\n int main() {\n Person* person = create_person("Alice", 25, 3);\n add_hobby(person, 0, "Reading");\n add_hobby(person, 1, "Swimming");\n // Intentional memory overrun to test the issue\n add_hobby(person, 3, "Cycling"); // This should cause corruption\n printf("%s's first hobby: %s\n", person->name, person->hobbies[0].name);\n free(person->hobbies);\n free(person);\n return 0;\n} ``` When I run this code, I get a segmentation fault intermittently, particularly when I try to access the hobbies after the memory overrun. I suspect that the issue is related to how I've managed memory with the `hobbies` array. I've already tried using tools like Valgrind to detect memory leaks and overruns, which confirmed that I'm writing out of bounds in the `add_hobby` function. However, I'm not sure how to prevent this corruption without drastically changing my data structures. Is there a recommended way to handle this situation, or any best practices for working with dynamically allocated nested structs to avoid this kind of error?