Question

Question #4

DO NOT USE ANY NON-STANDARD LIBRARY. o All the required libraries have already been included. O DO NOT INCLUDE ANY OTHER LIBRARY INTO THE CODE. o DO NOT ALTER THE NAMES OF THE C FILES PROVIDED. o DO NOT ALTER THE NAMES AND PROTOTYPES OF THE FUNCTIONS. DO NOT ALTER THE CODE, ONLY ADD WHATS NEEDED TO MAKE IT WORK.

This is the code:

#include <stdio.h>

/*
* This function counts and returns the number of adjacent Up and Downs in an array of integers.
* In other words, you should count and return the number of changing directions in the sequence.
* This means, for instance, if the sequence is entirely ascending, or entirely descending, it should return 0.
* Examples:
* For the sequence {1,2,3,5} starting from 1, you say "Up, Up, Up", so it returns 0, (no changing direction)
* For the sequence {0,2,1,7} starting from 0, you say "Up, Down, Up", so it returns 2, (two times of changing directions or two adjacent up/downs)
* For the sequence {2,3,1,4,5,2,1} starting from 2, you say "Up, Down, Up, Up, Down, Down", so it returns 3, (three adjacent up/downs)
* For the sequence {4,3,2,1} starting from 4, you say "Down, Down, Down", so it returns 0, (no changing direction)
*/
int adjacentUpDowns(int a[], int size);

int main(void) {

   int a[] = {1,2,3,5};
   int b[] = {0,2,1,7};
   int c[] = {2,3,1,4,5,2,1};
   int d[] = {4,3,2,1};

   printf("%d\n", adjacentUpDowns(a,4));   //Expected output is 0
   printf("%d\n", adjacentUpDowns(b,4));   //Expected output is 2
   printf("%d\n", adjacentUpDowns(c,8));   //Expected output is 3
   printf("%d\n", adjacentUpDowns(d,4));   //Expected output is 0
}

int adjacentUpDowns(int a[], int size) {

   // Complete the code of the function

}

Answer 1

Attched the c code. It has comments for explanation. If you have any doubts, you can talk about it in the comments.

Program Screenshot for Indentation Reference:

Sample Output:

Program code to copy:

#include <stdio.h>

/*
* This function counts and returns the number of adjacent Up and Downs in an array of integers.
* In other words, you should count and return the number of changing directions in the sequence.
* This means, for instance, if the sequence is entirely ascending, or entirely descending, it should return 0.
* Examples:
* For the sequence {1,2,3,5} starting from 1, you say "Up, Up, Up", so it returns 0, (no changing direction)
* For the sequence {0,2,1,7} starting from 0, you say "Up, Down, Up", so it returns 2, (two times of changing directions or two adjacent up/downs)
* For the sequence {2,3,1,4,5,2,1} starting from 2, you say "Up, Down, Up, Up, Down, Down", so it returns 3, (three adjacent up/downs)
* For the sequence {4,3,2,1} starting from 4, you say "Down, Down, Down", so it returns 0, (no changing direction)
*/
int adjacentUpDowns(int a[], int size);

int main(void) {

   int a[] = {1,2,3,5};
   int b[] = {0,2,1,7};
   int c[] = {2,3,1,4,5,2,1}; // it has 7 elements
   int d[] = {4,3,2,1};

   printf("%d\n", adjacentUpDowns(a,4));   //Expected output is 0
   printf("%d\n", adjacentUpDowns(b,4));   //Expected output is 2
   printf("%d\n", adjacentUpDowns(c,7));   //Expected output is 3 // correct the size to 7
   printf("%d\n", adjacentUpDowns(d,4));   //Expected output is 0
}

int adjacentUpDowns(int a[], int size) {

   // is size is <= 2 then return -
   if (size <= 2) {
       return 0;
   }

   int count = 0; // this is the count

   int lastStep = a[0] < a[1]; // last step: 1 for up and 0 for down

   // start at third element
   for (int i = 2; i < size; i++) {
       // check difference
       int compar = a[i - 1] < a[i];
       // is different from lastStep then update count
       if (lastStep != compar) {
           // update lastStep
           lastStep = compar;
           count++;
       }
   }
   // return count
   return count;
}