Chapter 5,Problem a: Let Us C by Yashawant Kanetkar solution manual

Problem Statement:

A 5-digit positive integer is entered through the keyboard,
write a function to calculate sum of digits of the 5-digit
number:
(1) Without using recursion
(2) Using recursion

Solution:

//Ahmad Furqan

//P5.a

#include <iostream>

#include <conio.h>

using namespace std;

int dig_sum(int num)

{

int sum = 0;

for (int i = 0; i < 5; i++) //5 iterations for each digit

{

sum += num % 10; //remainder of number divided with 10 is the rightmost digit

num = num / 10; //dividing number with 10 eliminates reightmost digit.

}

return sum;

}

int dig_sum_rec(int num)

{

if (num <10)

return num;

//return sum of rightmost digit and sum of digits of number without rightmost digit

return dig_sum_rec(num / 10) + (num % 10);

}

void main(void)

{

int num;

cout << "Enter 5 digit number:";

cin >> num;

cout << "Sum of digits without recursion: " << dig_sum(num);

cout << "\nSum of digits with recursion: " << dig_sum_rec(num);

_getch();

}