Sum of digits in C++ - c++

Question

program asked is sum of digits :
Input data are in the following format:
first line contains N - the number of values to process;
and then N lines will follow describing the values for which sum of digits should be calculated by 3 integers A B C;
for each case you need to multiply A by B and add C (i.e. A * B + C) - then calculate sum of digits of the result.
Answer should have N results, also separated by spaces
MY CODE IN C++ :
#include <iostream>
using namespace std;
int main ()
{
int n, a, b, c, t, sum = 0;
cin >> n;
for (int i = 0; i < n; i++)
{
cin >> a >> b >> c;
t = a * b + c;
while (t % 10 != 0)
{
sum = sum + t % 10;
t = t / 10;
}
while (t % 10 == 0)
{
sum = sum;
t = t / 10;
}
}
cout << " ";
cout << sum;
cout << " ";
return 0;
}
I'm having hard time correcting my code.
Any help is appreciated.
My assumption is there should be a better way to code this other than using 2 while loops.
PS : I checked other topics just want somebody that could help with my code thank you.

Answer 1

You don't need second while loop, and first one should be corrected to while (t != 0). After that your program for computing sum works correctly.
Try it online!
#include <iostream>
using namespace std;
int main ()
{
int n, a, b, c, t, sum = 0;
cin >> n;
for (int i = 0; i < n; i++)
{
cin >> a >> b >> c;
t = a * b + c;
while (t != 0)
{
sum = sum + t % 10;
t = t / 10;
}
}
cout << " ";
cout << sum;
cout << " ";
return 0;
}
Input:
1
123 456 789
Output:
33
Just noticed that you need N separate outputs instead of single sum (like you did), so then your program becomes like this:
Try it online!
#include <iostream>
using namespace std;
int main ()
{
int n, a, b, c, t, sum = 0;
cin >> n;
for (int i = 0; i < n; i++)
{
cin >> a >> b >> c;
t = a * b + c;
sum = 0;
while (t != 0)
{
sum = sum + t % 10;
t = t / 10;
}
cout << sum << " ";
}
return 0;
}
Input:
2
123 456 789
321 654 987
Output:
33 15