Question

• In Java
• Write a method named addDigits which accepts two inputs, num and index. The first input parameter num is a 4-digit positive integer and index is an int value which refers to a digit that the summation should start from. For example if the given num is 2345 and the index is 1, starting from the second digit, the result of 12 is returned which is the sum of 3, 4, and 5. If the num is not a 4-digit integer or it is a negative integer the method returns zero. Also, the result of zero is returned when index is not between [0-3].

• Examples:

addDigits(123, 1)-> 0

addDigits(7645, -1)-> 0

addDigits(7769, 3)-> 9

addDigits(4678, 2)-> 15

addDigits(3340, 0)-> 10

Answer 1

the given method returns the correct output for the given examples

please drop a comment of there's an issue.

the required method is given as follows:

//---------------------------------------------------------

static int addDigits(int number, int index){

        //converts the number to the string and checks the lenght of the string

        if (Integer.toString(number).length()!=4){

            return 0;

        }

        //checks if the index is negetive or greater than 3

        if (index<0 || index>3){

            return 0;

        }

        int sum=0;

        //iterates from 3 to 0

        for(int i=3; i>=0;i--){

            //slices the last digit of the number into the digit variable

            int digit=number%10;

            //slices the last digit of the number

            number=number/10;

            //adds to the digit to the sum if the current "i" is greater than equal to the index

            if(index<=i){

                sum=digit+sum;

            }

        }

        return sum;

    }