How to Use cin.fail() Method in C++?

// C++ program to use cin.fail() method
#include <iostream>
#include <limits>
using namespace std;
int main()
{
    // Declare and initialize integer variables.
    int i = 0, j = 0;
    // Infinite loop to continually ask for input until a
    // valid integer is entered.
    while (true) {
        // Ask the user to enter int value.
        cout << "Enter an Integer: " << endl;
        i++;
        // Read input from the user.
        cin >> j;
        // Check if the input operation failed (i.e., input
        // was not an integer).
        if (cin.fail()) {
            // Clear the error flags on the input stream.
            cin.clear();
            // leave the rest of the line
            cin.ignore(numeric_limits<streamsize>::max(),
                       '\n');
            // Ask the user to enter a valid int number only
            cout << "Wrong input, please enter a number: ";
        }
        else {
            // Print the valid integer entered by the user.
            cout << "Integer " << i << ": " << j << endl;
        }
    }
    return 0;
}