problem with cin's failbit

[RadWayne]

I have something similar to the following:

 int number;
 char ch;

 cin>>number;
 if(!cin){cout<<"Error\n";}
 cin>>ch;

entering a character when prompted for number triggers the cin failbit and prints "Error" but the character is then carried over and read into ch ending the program.

How do I tell it to forget the character and begin reading in a fresh line?

[kbw]

http://en.cppreference.com/w/cpp/io/basic_ios/clear

[RadWayne]

I tried to use both cin.clear() and cin.ignore() but neither seem to work.

As I understand cin.clear() just clears cin's error flags.

        int number;
 	char ch;

 	cin>>number;
 	if(!cin)
 	{
 		cout<<"Error\n";
 		cin.clear();
 	}
 	cin>>ch;

does the same thing as the original code.

[MiiNiPaa]

I tried to use both cin.clear() and cin.ignore()

Show how you used .ignore() and what behavior you expect on this input:

123X AB
C D

[RadWayne]

So in kbw's example:

double n;
    while( std::cout << "Please, enter a number\n"
           && ! (std::cin >> n) )
    {
        std::cin.clear();
        std::string line;
        std::getline(std::cin, line);
        std::cout << "I am sorry, but '" << line << "' is not a number\n";
    }
    std::cout << "Thank you for entering the number " << n << '\n';

cin.clear() is used to clear the error flag but then the excess/incorrect input is dumped into a string.

Instead of dumping the excess/incorrect input into a string is there any way to tell the computer to completely forget about it?

As for the input

123X AB
C D

in this simplified program it would read the number 1 into number and '2' into ch and then be done.

suppose the input was

AB

in this case I want to say 'A' is not an int and cannot be read into number. Now forget 'A' and store 'B' in ch.

[MiiNiPaa]

So you need to read only one

digit

? Your program reads all consequent digits until first whitespace. Look into .get() member function.