Comparison of iostreams and stdio

The stdio library served C programmers well for many years. However, it has several deficiencies:

• The use of functions, like printf(), that accept variable numbers and types of arguments mean that type checking is subverted at an important point in many programs.

• There is no mechanism for extending it to user defined classes. The only way to add new format specifiers to printf() is to reimplement it.

• The mechanism is closely tied to file I/O. sprintf() explicitly extends it to incore operations, but there is no general method for creating alternate sources and sinks of data.