Question

Write a program that prompts the user to enter an integer number between 1 and 999. The program displays the sum of all digits in the integer if the input is valid; otherwise, it displays a message indicating that the integer is not between 1 and 999 and hence, is invalid.

Name the program file Q1.cpp

Example: if the user enters 12, sum of digits is 3.

If the user enters 122, sum of digits is 5.

Answer 1

#include <iostream>

using namespace std;

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

    if (n < 1 || n > 999) {
        cout << "Input is invalid!" << endl;
    } else {
        int sum = 0;
        while (n > 0) {
            sum += n % 10;
            n /= 10;
        }
        cout << "sum of digits is " << sum << "." << endl;
    }
    return 0;
}