From the “things that really shouldn’t be difficult, but for some reason are anyway” department comes the following. Do you think you know how to program in C++? Familiar with objects and polymorphism and templates and everything? Then this should be dead easy. Should, I said.
Problem: Write a function that takes in a
std::istreamand a size
nand returns a
std::string. The string should contain the first
ncharacters of the input stream, with all formatting (whitespace, newlines, etc) preserved.
You can ignore all concerns about multi-byte characters for the sake of this problem. Sounds simple, right? You’d be able to crank this out in ten seconds if someone asked you this in an interview, right? Okay, now try it with this caveat.
Caveat: You must do this in a purely C++ “style”. To be precise, you must do this without using any character variables or character arrays. Use only a
std::stringobject (or some other memory-managed object in the standard library) as your input buffer.
For as much as the C++ STL tries to encourage you to use RAII-oriented containers instead of raw arrays, this seemingly trivial task requires some surprisingly baroque coding. If you want to test yourself, try writing the function before you click more.