Write a C++ Program to find the Sum of Digits in a Number using a While loop with an example. Within the while loop, it divides the number into individual digits and then finds the sum of it.
Here, we used a cout statement to show you the value of the remainder and sum value in iteration wise which helps you can understand the execution.
#include<iostream> using namespace std; int main() { int number, reminder, digitSum = 0; cout << "Please Enter the Number to calculate Sum of Digits = "; cin >> number; while (number > 0) { reminder = number % 10; digitSum += reminder; number = number / 10; cout << "\nDigit = " << reminder << " and the Digit Sum = " << digitSum; } cout << "\n\nThe Sum of all Digits in a given Number = " << digitSum; return 0; }

C++ Program to find Sum of Digits in a Number using a For Loop
#include<iostream> using namespace std; int main() { int number, reminder, digitSum; cout << "Please Enter the Number to calculate Sum of Digits = "; cin >> number; for(digitSum = 0; number > 0; number = number / 10) { reminder = number % 10; digitSum += reminder; cout << "\nDigit = " << reminder << " and the Digit Sum = " << digitSum; } cout << "\nThe Sum of all Digits in a given Number = " << digitSum; return 0; }
Please Enter the Number to calculate Sum of Digits = 785469
Digit = 9 and the Digit Sum = 9
Digit = 6 and the Digit Sum = 15
Digit = 4 and the Digit Sum = 19
Digit = 5 and the Digit Sum = 24
Digit = 8 and the Digit Sum = 32
Digit = 7 and the Digit Sum = 39
The Sum of all Digits in a given Number = 39
C++ Program to find Sum of Digits in a Number using functions
In this C++ example, we separated the logic using functions.
#include<iostream> using namespace std; int sumOfDigits(int number) { int reminder, digitSum; for(digitSum = 0; number > 0; number = number / 10) { reminder = number % 10; digitSum += reminder; cout << "\nDigit = " << reminder << " and the Digit Sum = " << digitSum; } return digitSum; } int main() { int num, digiSum; cout << "Please Enter the Number to calculate Sum of Digits = "; cin >> num; digiSum = sumOfDigits(num); cout << "\nThe Sum of all Digits in a given Number = " << digiSum; return 0; }
Please Enter the Number to calculate Sum of Digits = 78932
Digit = 2 and the Digit Sum = 2
Digit = 3 and the Digit Sum = 5
Digit = 9 and the Digit Sum = 14
Digit = 8 and the Digit Sum = 22
Digit = 7 and the Digit Sum = 29
The Sum of all Digits in a given Number = 29
C++ Program to find Sum of Digits in a Number using Recursion
#include<iostream> using namespace std; int sumOfDigits(int number) { static int reminder, digitSum = 0; if(number > 0) { reminder = number % 10; digitSum += reminder; sumOfDigits(number / 10); return digitSum; } else return 0; } int main() { int num, digiSum; cout << "Please Enter the Number to calculate Sum of Digits = "; cin >> num; digiSum = sumOfDigits(num); cout << "\nThe Sum of all Digits in a given Number = " << digiSum; return 0; }
Please Enter the Number to calculate Sum of Digits = 248769
The Sum of all Digits in a given Number = 36