MATLAB: How to modify an array’s elements using another element

arrayfor loop

I need to write a for loop that will set each array element in bonusScore to the sum of itself and the next element (except for the last element which stays the same). Why why does my code yield these (incorrect) output numbers? What should I do to fix my code?
function bonusScores = CombineScores(numberScores, userScores)
   for i = 1:numbersScores;
        userScores(1) = userScores(1) .* 2 + userScores(2);
        userScores(2) = userScores(2) .* 2 + userScores(3);
        userScores(3) = userScores(3) .* 2 + userScores(4);
        bonusScores = userScores;
   end
end
Input: CombineScores(4, [10, 20, 30, 40]) Output: ans = 1800, 1960, 1080, 40

Best Answer

Fix code:
function bonusScores = CombineScores(numberScores, userScores)
for i = 1:numberScores-1
    userScores(i) = userScores(i) + userScores(i+1);
end
bonusScores = userScores;
end
Try
>> CombineScores(4, [10, 20, 30, 40])
ans =
      30    50    70    40
Related Question