Question

You are given an array named digits of digitCapacity that holds the individual digits of a very large number in such a way that the least significant digit of any given number is located at element index zero The number of valid digits in the array is held by a variable named digitNumber. All the values above digitNumber elements are always zero, no matter how large the array itself is. However, some transactions cause the digitNumber to misrepresent the correct number of valid digits, and is found to be too large A method named reset NumDigits is used to decrease the digit Number down to where it does not count leading zeros and represents the correct number of valid digits. From the following select the most correct code segment that would be used in the reset NumDigits method. o 1,- All of these selections are correct 2. for Index - digitCapacity digits index ) - 0 Index -> 4 digit amb 3. - while( digits digitNumber ) - 0) 1 digitamber - digitNumber - 1: 3 None of these selections is correct while digital digitanber - 1) -O) dagstaber- 3 for Index - digitumber: digital digitNumber - 1) = 0; index++) 1 digit Sunber-1

Answer 1

while( digits[digitNumber-1] == 0)
{
        digitNumber--;
}

This segment is correct . Let say we have 11111110000000 as the array . Then suppose digitNumber is holding the 9th position (0-based index) . But originally it should be holding 6th position as after that all the values are zero. so going by this code whenever we have 0 value at digitNumber index we will decrease it's position(so to bring the digitNumber at its correct place) . After 3 loops we will have digitNumber at 6th position as required.

In the 5th segment we will not reach the correct position as it checking the value one less than it so digitNumber will stop at one place ahead of it .

In the 6th segment we are not checking the values uptill the msb instead we are getting towards the farther end of the array which is of no use and have leading zeroes.

In the 2nd segment , we are checking from the farthest end of the array which sometimes may have digitNumber at the place but not all times . so we should just start checking from the place currently hold by the digitNumber and not some other place.