sum of array every frame

how can i sum of array on every frame?If the value of one of the arrays is reduced,and again sum of array;

 void spawn{
 numberofobject[i]--;
 }
   
 {
   for (int i = 0; i <.numberofobject[i]; i++)
                 {
         Sumofobject +=numberofobject[i];
                 }
 }