Incomprehensible Infinite Loop

As far as I understand it, the operator >> is capable of accepting integer arguments when used with the cin stream.

The problem is, when I go crazy on the keyboard and type in a group of numerical characters which far exceeds the size of an integer (on an intel based computer with VC++ 2003) such as 1872634817236491872364817, the value that gets passed to my integer is always (and I mean always) 3435973836.

That is certainly a head scratcher but I have this stream nested inside a while loop and once it receives my crazy input, it never stops at cin and continues going round and round and always passes 3435973836 to my integer.

Here's my code:

Code:

while(true)
{
	cin >> input; // input is an integer. Feel free to type in 
			//any very large number at the prompt. Just make 
			//sure it exceeds 2^32. Preferrably much larger.
	s = factorialize(input); // s was declared as a string elsewhere.
	cout << s.c_str() << endl;
}

On the off chance that my function "factorialize" is causing the damage, here's the relevant function:

Code:

string factorialize(unsigned int input)
{
	bool not_end = false;
	unsigned int max = static_cast<int>(sqrt(static_cast<double>(input)));
	string s;
	for(unsigned int i = 2; i <= max; i++)
	{
		if(input % i == 0)
		{
			char buf[10];
			itoa(i, buf, 10);
			s += buf;
			s += "x";
			s += factorialize(input/i);
			not_end = true;
			break;
		}
	}
	if(!not_end)
	{
		char buf[10];
		itoa(input, buf, 10);
		s = buf;
	}
    return s;
}

What in the world is going on here?

As always, I humbly await your responses.

Don't worry its not your function it is cin
I thought there was a way to validate if what the user inputed was a valid integer datatype and if it wasn't you could just prompt again, but I can't remember.

I dunno. Maybe try flushing cin down the toilet. [This isn't the technical definition of whats really going on, but by golly it should be!]

Code:

cin.clear();

Code:

while(true)
{
	cin >> input;
cin.clear(); // Give that sucker a nice swirly right here. Note last valid INPUT will be processes TWICE as the junk INPUT.. say 12397329478729348782 will be gone.
	count = 0;
	s = factorialize(input);
	cout << s.c_str() << endl;

}

The result of reading an integer is implementation defined if the actual input corresponds to a larger value than the integer can store, and a stream will typically be in an error state afterwards. Which (roughly) means the result is compiler and library specific.

cin >> var; has all the same problems that scanf() has in C
- No overflow detection
- Poor error recovery
- leaves unused characters (eg newlines) to foul up other input methods.

If you really want to be sure of what you're getting, you have to read all user input as a string, and then validate it yourself.

Thanks guys. I guess it should have been obvious all along.