A C++ lambda looks like a small function literal — write some captures in brackets, parameters in parens, and a body in braces, and you have a callable. What the compiler actually produces is something heavier and more interesting: a…

Graphics APIs were designed for C, and they show their lineage in the same place every C-style API does: resource lifetimes are the caller’s problem. glGenBuffers hands you a GPU resource identified by an integer handle. glDeleteBuffers releases it. Forget to call the second…

Some problems genuinely require holding a value whose type isn’t known until run time — plug-in systems where a host loads arbitrary user data, generic event-handler context attached to messages, configuration values from a file whose schema isn’t known at…

Adding a single virtual function to a class quietly changes the shape of every object it creates. The class gets larger by the size of one pointer, gains a hidden data member that the language never lets you name, and becomes a…

Defining a comparable type in pre-C++20 code meant writing six operators: ==, !=, <, <=, >, >=. Each one took an argument of the same type, did its own member-by-member walk, and returned bool. Almost every line was redundant — the same comparisons computed three different ways…

C++ and C produce object files that look almost identical to a linker, but the symbol names inside them follow different rules. A C++ compiler decorates function names with their parameter types — name mangling — so that overloaded functions can coexist…

C++’s friend keyword is a blunt instrument. The standard reference describes it plainly: “A friend is permitted full access to private and protected members.” There is no syntax for “this class can call my flush() method but not touch my internal buffer.” If Bar needs access…

std::string offers two ways to read a character at a position: s[i] and s.at(i). They look interchangeable, and for a valid index they are. The difference shows up at exactly the moment you care most — when i is out of range. operator[] produces undefined behaviour; at() throws std::out_of_range. The choice…

C++17’s class template argument deduction (CTAD) lets you write std::pair p{1, 2} instead of std::pair<int, int> p{1, 2} — the compiler figures out the template arguments from the constructor call. For most class templates this works automatically, because the compiler synthesises an implicit deduction guide from…

Virtual functions are how C++ usually does polymorphism, and the mechanism is well understood: each polymorphic object carries a hidden pointer to a vtable, and a virtual call is compiled into an indirect jump through that table. The cost is…