Name: C
Author: ivangdavila

Quick Reference

| Topic | File |

|-------|------|

| malloc/free, leaks, double free | memory.md |

| Null, dangling, pointer arithmetic | pointers.md |

| Null terminator, buffer overflow | strings.md |

| Integer overflow, signed/unsigned | types.md |

| Macro traps, include guards | preprocessor.md |

| Common undefined behavior | undefined.md |

Critical Rules

malloc returns void* — cast required in C++, optional in C but check for NULL
free(ptr); ptr = NULL; — always null after free to prevent double-free
sizeof(array) in function gives pointer size, not array size — pass length separately
char str[5] = "hello"; — no room for null terminator, UB when used as string
strcpy doesn't check bounds — use strncpy and manually null-terminate
Signed overflow is UB — compiler can optimize assuming it never happens
i++ + i++ is UB — no sequence point between modifications
Returning pointer to local variable — dangling pointer, UB on use
#define SQUARE(x) xx — SQUARE(1+2) = 1+21+2 = 5, not 9
memcpy with overlapping regions — use memmove instead
Uninitialized variables — contain garbage, UB if used
Array out of bounds — no runtime check, silent corruption or crash