C++

Quick Reference

| Topic | File | |-------|------| | RAII, smart pointers, new/delete | memory.md | | Raw pointers, references, nullptr | pointers.md | | Rule of 3/5/0, inheritance, virtual | classes.md | | Containers, iterators, algorithms | stl.md | | Templates, SFINAE, concepts | templates.md | | Threads, mutex, atomics | concurrency.md | | C++11/14/17/20, move semantics | modern.md | | Undefined behavior traps | ub.md |

Critical Rules

• Raw new without delete leaks — use std::unique_ptr or std::make_unique
• Returning reference to local — undefined behavior, object destroyed on return
• == for C-strings compares pointers — use std::string or strcmp()
• Signed integer overflow is UB — not wrap-around like unsigned
• Virtual destructor required in base class — otherwise derived destructor skipped
• std::move doesn't move — it casts to rvalue, enabling move semantics
• Moved-from object valid but unspecified — don't use without reassigning
• Data race on non-atomic is UB — use std::mutex or std::atomic
• vector<bool> is not a real container — returns proxy, use deque<bool>
• map[key] inserts default if missing — use find() or contains() to check
• Braced init {} prevents narrowing — int x{3.5} errors, int x(3.5) truncates
• Iterator invalidation on push_back — vector may relocate, invalidating iterators
• string_view doesn't own data — underlying string must outlive the view