Simple Program in Looping.

1.Sum of Digit
Code:
let num = 1234;
let sum = 0;

while (num > 0) {
let digit = num % 10;

sum = sum + digit;

num = Math.floor(num / 10);
}

console.log("Sum of digits:", sum);

Step-by-step Explanation:

Let’s say num = 1234

Step 1:
digit = 1234 % 10 = 4
sum = 0 + 4 = 4
num = 1234 / 10 = 123.4 → 123

Step 2:
digit = 123 % 10 = 3
sum = 4 + 3 = 7
num = 12

Step 3:
digit = 12 % 10 = 2
sum = 7 + 2 = 9
num = 1

Step 4:
digit = 1 % 10 = 1
sum = 9 + 1 = 10
num = 0 → loop stops

Final Output: 10

Screenshot of the Program:

2.Reverse a Number
Code:
let num = 1234;
let reverse = 0;

while (num > 0) {
let digit = num % 10;

reverse = reverse * 10 + digit;
num = Math.floor(num / 10);
}

console.log("Reversed number:", reverse);

Step-by-step Explanation:

Let’s say num = 1234

Step 1:
digit = 4
reverse = 0 * 10 + 4 = 4
num = 123
Step 2:
digit = 3
reverse = 4 * 10 + 3 = 43
num = 12
Step 3:
digit = 2
reverse = 43 * 10 + 2 = 432
num = 1
Step 4:
digit = 1
reverse = 432 * 10 + 1 = 4321
num = 0 → loop stops

** Final Output:** 4321

Screenshot of the Program: