Question

How to replace every element in array by multiplication of next and previous elements with C++

Answer 1

// arr[first] = arr[first] (itself) * arr[next];
// arr[last] = prev * arr[last] (itself);

#include <iostream>

void MultiplyNextPrevious(int arr[], int size) {
    if (size <= 1)
        return;
 
    int prev = arr[0];
    
    arr[0] = arr[0] * arr[1];

    
    for (int i = 1; i < size - 1; i++) {
        int curr = arr[i];
 
        arr[i] = prev * arr[i + 1]; // arr[i + 1] = next
 
        prev = curr;
    }

    arr[size - 1] = prev * arr[size - 1];
}
 
int main()
{
    int arr[] = {2, 3, 5, 6, 12, 8, 10, 7};
    
    int size = sizeof(arr) / sizeof(arr[0]);
    
    MultiplyNextPrevious(arr, size);
    
    for (int i = 0; i < size; i++)
        std::cout << arr[i] << " ";
}




/*
run:

6 10 18 60 48 120 56 70 

*/

 

70+ SQL courses for beginners and professionals