Not sure if I should be using seekg()

Just a simple question. I created a function to validate numeric data coming in from cin. I read the posts and some say to use ignore(5000,'\n') or some other huge number. I found that seekg(o,ios::end); seems to work as well but I am not sure if it is going to cause any problems? I would think that it seeks to the end of the stream and effectively ignores all data in the stream. I am just not sure if this is the proper way to use seekg(). Anyway here is my simple function.

Code:

int validate_input(const char*message)
	{
		int num;
		char ch;
		cout<<message;
		while( (ch=	cin.get() )!='\n')
			{
			if((ch>='0' ) && (ch<='9'))
				{
					cin.putback(ch);
					cin>>num;
				}
					else
				{
					cin.clear();
					//cin.ignore (50000,'\n');
					cin.seekg(0,ios::end);
					cout<<"invalid input Please reenter: \n";
					cout<<message;
				
				}
			}
		return num;
	}

Another way of getting numbers is to read as a string and convert:
http://faq.cprogramming.com/cgi-bin/...&id=1043284385

Some flush info
http://faq.cprogramming.com/cgi-bin/...&id=1043284392

and some more
http://faq.cprogramming.com/cgi-bin/...&id=1043284392

I had already read up on those thanks though. I guess I am just trying to answer the question if seekg() can be used the same as the ignore statement. The ignore reads in the characters and then discards where seekg() seeks to the end. What happens to the contents of the buffer when it reaches the end? Are they discarded? seekg doesn't read each character does it? it just goes to the end.

>if seekg() can be used the same as the ignore statement
It really depends on the semantics of seeking with cin. To my knowledge, whether cin is seekable or not (and what happens if it is) is unspecified. Ignore would be the more appropriate solution:

Code:

#include <limits>
...
cin.ignore ( numeric_limits<streamsize>::max(), '\n' );