Variadic templates

Probably the greatest difference between generic programming in C and C++ is type safety. It is possible to write generic code in C—the standard function qsort() is a perfect example—it can sort values of any type and they are passed in using a void* pointer, which can really be a pointer to any type. Of course, the programmer has to know what the real type is and cast the pointer to the right type. In a generic C++ program, the types are either explicitly specified or deduced at the time of the instantiation, and the type system for generic types is as strong as it is for regular types. Unless we want a function with an unknown number of arguments, that is, prior to C++11, the only way was the old C-style variadic functions where the compiler had no idea what the argument types were; the programmer just had to know and unpack the variable arguments correctly.

C++11 introduced the modern equivalent to a variadic function—a variadic template...