template <class InputIterator, class T>
T accumulate(InputIterator first, InputIterator last, T init);
template <class InputIterator, class T, class BinaryFunction>
T accumulate(InputIterator first, InputIterator last, T init,
BinaryFunction binary_op);
DescriptionAccumulate is a generalization of summation: it computes the sum (or some other binary operation) of init and all of the elements in the range [first, last). [1]
The function object binary_op is not required to be either commutative or associative: the order of all of accumulate's operations is specified. The result is first initialized to init. Then, for each iterator i in [first, last), in order from beginning to end, it is updated by result = result + *i (in the first version) or result = binary_op(result, *i) (in the second version).
Definition Defined in the standard header numeric, and in the nonstandard backward-compatibility header algo.h. Requirements on types For the first version, the one that takes two arguments:int main()
{
int A[] = {1, 2, 3, 4, 5};
const int N = sizeof(A) / sizeof(int);
cout << "The sum of all elements in A is "
<< accumulate(A, A + N, 0)
<< endl;
cout << "The product of all elements in A is "
<< accumulate(A, A + N, 1, multiplies<int>())
<< endl;
}
Notes
[1] There are several reasons why it is important that accumulate starts with the value init. One of the most basic is that this allows accumulate to have a well-defined result even if [first, last) is an empty range: if it is empty, the return value is init. If you want to find the sum of all of the elements in [first, last), you can just pass 0 as init.
See alsoinner_product, partial_sum, adjacent_difference, count STL Main PageRetroSearch is an open source project built by @garambo | Open a GitHub Issue
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