Sum of first and last digit of a number in C++

#include <iostream>

int main() {
    int number, lastDigit, firstDigit, tempNumber;

    std::cout << "Enter an integer: ";
    std::cin >> number;

    lastDigit = number % 10;

    tempNumber = number;
    while (tempNumber >= 10) {
        tempNumber /= 10;
    }
    firstDigit = tempNumber;

    int sum = firstDigit + lastDigit;

    std::cout << "Sum of first and last digit of " << number << " is: " << sum;

    return 0;
}