10018 w/ Comments & Details

#include<iostream>
using namespace std;

/* Function for Determining the Reverse Number */
long long int rev(long long int x) //The Parameter takes the Number as Input (as "x"), sent by the Main Function
{
    long long int rn = 0; //the reversed number will be stored in "rn"

    for (x ; x>0 ; x/= 10) //loop for calculation of the reversed number
        rn = ((rn * 10) + (x % 10)); //simple mathematics logic

    return rn; //returns the reversed number.
}

int main()
{
    int T, a; //"T" is for TestCase, "a" is for number of attempts.
    long long int P, rP; //"P" is the Number entered by user, "rP" is the reversed number of "P".

    cin >> T; //takes input of the Number of TestCases
    while (T--)
    {
        cin >> P; //input of the original number entered by user
        a = 1; //sets number of attempt to 1, as it's the first attempt
        rP = rev(P); //calls the reverse function and sends the value of "P".
                //in return it gets the reversed number of "P" and assigns it to "rP"
        while (1)
        {
            P = P + rP; //adds up the original number and the reversed number
                    //and assigns the sum to "P"(the original Number)
            rP = rev(P); //reverses the sum and assigns it to "rP"
            if (P - rP == 0){ //checks if the sum ("P") is Palindrome
                cout << a << " " << P << endl; //(prints the number of attempts
                                //and the Palindrome Number (Current Value of "P"
                break; //if Palindrome, this breaks the loop as we don't need it anymore.
            }
            else
                a++; //if the value of "P" is NOT Palindrome, it increases the number of attempts
                    //and continues the reverse and add process
                if(a>999) //if the number of attempts is NOT Less than 1000, this breaks the loop
                    break;
        }
    }

    return 0;
}