C++ program to compute the sum of digits in a given numbers

In this tutorial, we will discuss a concept of C++ program to compute the sum of digits in a given numbers

In C++ programming language, we can use for loop ,while loop and do-while loop to compute the sum of digits in a given numbers

In this article, we are going to learn how to find the sum of digits in a given number in C++ language

program to calculate the sum of digits

Compute the sum of digits in a given number using for loop

Program 1

#include <iostream>
#include <conio.h>
using namespace std;

int main()
{
    long num,counter,digits,sum=0;
    cout<<"Enter a number of find sum of digits\n";
    cin>>num;//get input from the user for find sum of digits

for(counter=num; num>0; num/=10)
{
    digits=num%10;
    sum=sum+digits;

}
cout<<"Given number is:" <<counter;

cout<<"\nSum of the digits is"<<counter <<"is :" << sum;
getch();
    return 0;
}

When the above code is executed, it produces the following results

Case 1

Enter a number for find sum of digits
1010
Given number is:1010

Sum of the digits  1010 is = 2

Case 2

Enter a number for find digits sum
54321
Given number is:54321

Sum of the digits  54321 is = 15

Compute the sum of digits in a given number using while loop

Program 2

#include <iostream>
#include <conio.h>
using namespace std;

int main()
{
    long num,counter,digits,sum=0;
    cout<<"Enter a number of find sum of digits\n";
    cin>>num;//get input from the user for find sum of digits

counter=num;
while( num>0)
{
    digits=num%10;
    sum=sum+digits;
     num/=10;

}
cout<<"Given number is:" <<counter;

cout<<"\nSum of the digits is"<<counter <<"is :" << sum;
getch();
    return 0;
}

When the above code is executed, it produces the following results

Case 1

Enter a number for find sum of digits
1090
Given number is:1090

Sum of the digits  1090 is = 10

Case 2

Enter a number for find digits sum
123456
Given number is:123456

Sum of the digits  123456 is = 21

Compute the sum of digits in a given number using do-while loop

Program 3

#include <iostream>
#include <conio.h>
using namespace std;

int main()
{
    long num,counter,digits,sum=0;
    cout<<"Enter a number of find sum of digits\n";
    cin>>num;//get input from the user for find sum of digits

counter=num;

do{
    digits=num%10;
    sum=sum+digits;
     num/=10;

}while( num>0);
cout<<"Given number is:" <<counter;

cout<<"\nSum of the digits is"<<counter <<"is :" << sum;
getch();
    return 0;
}

When the above code is executed, it produces the following results

Case 1

Enter a number for find sum of digits
11001100
Given number is:11001100

Sum of the digits  11001100 is = 4

Case 2

Enter a number for find digits sum
876543
Given number is:876543

Sum of the digits  876543 is = 33

Methods

Declare the variable num, count and digits as long type.
Declare and initialize variable sum to Zero.
Receive input from the user for the value to store the variable num and to find the sum of digits
Using a loop (for loop, while loop, do-while loop) get each digit of the number and add it to the to a variable to find the sum.
Display the sum of the digits of the number.