Question

Write in C++ a function int sumofdigits( int n ) which computes and returns the sum of the digits of
n.
Use the following main function to test your code:
int main()
{
int n, sn;
cout << "Enter q to quit or an integer: ";
while ( cin >> n )
{
sn = sumofdigits(n);
cout << "sumofdigits( " << n << " ) = " << sn;
cout << "\nEnter q to quit or an integer: ";
}
return 0;
}

Sample output:
Enter q to quit or an integer: 0
sumofdigits( 0 ) = 0
Enter q to quit or an integer: 23
sumofdigits( 23 ) = 5
Enter q to quit or an integer: -345
sumofdigits( -345 ) = 12
Enter q to quit or an integer: 100
sumofdigits( 100 ) = 1
Enter q to quit or an integer: 4
sumofdigits( 4 ) = 4
Enter q to quit or an integer: -345216
sumofdigits( -345216 ) = 21
Enter q to quit or an integer: q

Note: It must compile on its own and have the functions with the correct types and names.

Answer 1

#include <iostream>

using namespace std;

int sumofdigits(int n) {
    if (n == 0)
        return 0;
    else if (n < 0)
        return sumofdigits(-1*n);
    else
        return (n % 10) + sumofdigits(n/10);
}

int main() {
    int n, sn;
    cout << "Enter q to quit or an integer: ";
    while (cin >> n) {
        sn = sumofdigits(n);
        cout << "sumofdigits( " << n << " ) = " << sn;
        cout << "\nEnter q to quit or an integer: ";
    }
    return 0;
}