I want to know how `malloc` and `free` work. ``` int main() { unsigned char *p = (unsigned char*)malloc(4*sizeof(unsigned char)); memset(p,0,4); strcpy((char*)p,"abcdabcd"); // **deliberately storing 8bytes** cout << p; free(p); // Obvious Crash, but I need how it works and why crash. cout << p; return 0; } ``` I would be really grateful if the answer is in depth at memory level, if it's possible.