Error handling with C-string input using get() and getline()

Question

I've just learned the basics of c-strings and how to read line oriented input. I noticed that fail bits are set for each function. However, not every problem sends a fail bit, so I thought this would be a good exercise to try and target two user input errors:

1. The user enters no input
2. The user enters more input than the allocated number of elements

/*Simple Error handle using get() and getline() *with too much input or no input on c-style strings */ #include <iostream> #include <string> #include <limits> int main() { const int size = 10; std::cout << "Please enter your name and hit enter. Then have your friend do the same\n\n"; //Using get() std::cout << "Your name: "; char name1[size]; while (!std::cin.get(name1, size) || std::cin.get() != '\n') { if (!std::cin) { std::cout << "No input\n"; std::cin.clear(); std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n'); } else { std::cout << "Name entered was too large for allocated memory...\n"; } std::cout << "Try again: "; } //using getline() std::cout << "Your friends name: "; char name2[size]; while (!std::cin.getline(name2, size) || name2[0] == NULL) { if(name2[0] == NULL){ std::cout << "No input\n"; } else { std::cout << "Name entered was too large for allocated memory...\n"; std::cin.clear(); std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n'); } std::cout << "Try Again: "; } std::cout << "\nNAME1: " << name1 << " NAME2: " << name2 << "\n"; std::cin.get(); return 0; } 

Answer 1

Writing all the code in a single huge main() is not only hard to read, but also a poor use of your skills. Write a re-usable function to prompt and read input from a supplied std::istream&. That will make it easier to test using a std::istringstream, too.

name2[0] == NULL looks like a pointer comparison. You probably want to compare against '\0' so that it's clear we're dealing with characters.

Both loops cycle indefinitely when we reach end of input stream. We probably should abort if std::cin.eof().

The final std::cin.get() seems pointless, as we just discard the result.

return 0; can be omitted - just reaching the end of main() is equivalent.