Govt. Exams
Entrance Exams
Buffer overflow by accessing beyond allocated boundaries causes segmentation fault as it accesses invalid memory pages.
A circular buffer requires head and tail pointers minimum to track current positions in the circular structure.
realloc() attempts to expand memory in place if possible; if not, allocates new block, copies old data, and frees old block.
A 2D array created with double pointers requires freeing each row first, then the pointer array itself to avoid memory leaks.
Calling free() on a pointer that wasn't returned by malloc/calloc/realloc causes undefined behavior, potentially corrupting the heap and crashing the program.
calloc(50, sizeof(struct Node)) allocates memory for 50 elements of struct Node size and initializes all bytes to zero, which is ideal when you need initialized memory.
Dynamic allocation allows using memory proportional to actual input size, preventing TLE from stack overflow with large static arrays and enabling solutions for variable-sized problems.
Using dynamic adjacency lists, you allocate V list pointers and E edge nodes total, giving O(V + E) space complexity, which is optimal for sparse graphs.
while(1) { int *arr = malloc(1000000); }
This creates an infinite loop that allocates 1MB each iteration without freeing, rapidly exhausting available memory. This is a classic memory leak scenario.
Strings in C are null-terminated, so allocating strlen(s)+1 bytes ensures space for the null terminator. This is the standard safe approach.
