# Sum of given number

### General Algorithm for sum of digits in a given number:

• Get the number
• Declare a variable to store the sum and set it to 0
• Repeat the next two steps till the number is not 0
• Get the rightmost digit of the number with help of the remainder ‘%’ operator by dividing it by 10 and add it to sum.
• Divide the number by 10 with help of ‘/’ operator to remove the rightmost digit.
• return the sum

### Solution-1

```function sumOfDigits(n) {
let sum = 0;

while(n < 0) {

// get the last digit
sum = sum + n % 10;

// divide the number by 10 we get float
// parse the number to int to remove last digit
n = parseInt(n / 10);
}

return sum;
}

console.log(sumOfDigits(123));
```

### Solution-2:

```function sumOfDigits(n) {
let sum;

for(sum = 0; n > 0;
sum += n % 10,
n = parseInt(n / 10));

return sum;
}

console.log(sumOfDigits(123));
```

### Solution-3:

```function sumOfDigits(n) {
return n == 0 ? 0 : n % 10 + sumOfDigits(parseInt(n/10));
}

console.log(sumOfDigits(123));```