//Syntax
accumulate(first, last, sum);
accumulate(first, last, sum, myfun);
first, last : first and last elements of range
whose elements are to be added
sum : initial value of the sum
myfun : a function for performing any
specific task. For example, we can
find product of elements between
first and last.
//Example
int a[] = {5 , 10 , 15} ;
int res = accumulate(a,a+3,0); // 30