Double the First Element and Move Zero to End in C++

In this tutorial, we are going to write a program that doubles the first element and moves all the zeroes to the end of the given array.

We have to double a number when there are tow the same elements in adjacent indices. After that, we have to add a zero to the array.

Move all the zeroes in the array to the end.

Example

Let's see the code.

 Live Demo

#include <bits/stdc++.h>
using namespace std;
void moveZeroesToEnd(int arr[], int n) {
   int count = 0;
   for (int i = 0; i < n; i++) {
      if (arr[i] != 0) {
         arr[count++] = arr[i];
      }
   }
   while (count < n) {
      arr[count++] = 0;
   }
}
void updateAndRearrangeArray(int arr[], int n) {
   if (n == 1) {
      return;
   }
   for (int i = 0; i < n - 1; i++) {
      if ((arr[i] != 0) && (arr[i] == arr[i + 1])) {
         arr[i] = 2 * arr[i];
         arr[i + 1] = 0;
         i++;
      }
   }
   moveZeroesToEnd(arr, n);
}
void printArray(int arr[], int n) {
   for (int i = 0; i < n; i++)
      cout << arr[i] << " ";
}
int main() {
   int arr[] = { 2, 3, 3, 4, 0, 5, 5, 0 }, n = 7;
   cout << "Given Array: ";
   printArray(arr, n);
   cout << endl;
   updateAndRearrangeArray(arr, n);
   cout << "Updated Array: ";
   printArray(arr, n);
   cout << endl;
   return 0;
}

Output

If you execute the above program, then you will get the following result.

Given Array: 2 3 3 4 0 5 5
Updated Array: 2 6 4 10 0 0 0

Conclusion

If you have any queries in the tutorial, mention them in the comment section.