Trapping input

Im kinda newbish right now, but is there a way to stop people from entering the wrong type of input?

Code:

     main()
      {
        int a;
        cout << "Enter a number";
        cin >> a;
      }

If they enter a char for the input the program locks-up. Is there a way to catch those?

Code:

#include <iostream>

using namespace std;

int main()
{
	int a;
	bool flag = false;
	for (;;)
	{
		cout << "Enter a number: ";
		cin >> a;
		if (cin.fail())
		{
			cin.clear();
			cin.ignore(100, '\n');
			cout << "Invalid Input!\n";
		}
		else
			break;
	}
	cout << "Your number is: " << a << endl;
	return 0;
}

Thanks