Answer:
for (int i = 0; i < arr.length - 1; i++){
arr[i] = arr[i] + arr[i+1];
}
Step-by-step explanation:
The above code has been written using Java.
Let the given array be arr.
To set each element in the array (except the last element) to the sum of itself and the next element, ;
=> first create a loop that cycles through the array from the first element (zeroth index) to the penultimate element as follows;
for (int i = 0; i < arr.length - 1; i++) {
}
=> at each of the cycles of the loop, the array element at that position (dictated by the value of i) is assigned a new value equal to the sum of its old value and the value of the next element to it as follows;
arr[i] = arr[i] + arr[i+1]
where arr[i] is the current array element and arr[i+1] is the next array element to the current element.
Putting all of these together, we have
for (int i = 0; i < arr.length - 1; i++){
arr[i] = arr[i] + arr[i+1];
}
Notice that the loop goes from i=0 to i < arr.length-1. This shows that the loop will not directly get to the last element (where i = arr.length-1), thereby leaving the last element unchanged.