Syntax:
#include <numeric> TYPE accumulate( input_iterator start, input_iterator end, TYPE val ); TYPE accumulate( input_iterator start, input_iterator end, TYPE val, BinaryFunction f );
The accumulate function computes the sum of val and all of the elements in
the range [start,end).
If the binary function f is specified, it is used instead of the + operator to
perform the summation.
The accumulate function runs in linear time.
For example, the following code uses accumulate to sum the integers in a vector:
#include <iostream> using std::cout; #include <vector> using std::vector; #include <numeric> using std::accumulate; int main() { vector<int> v; const int START = 1, END = 10; for( int i = START; i <= END; ++i ) v.push_back(i); int sum = accumulate( v.begin(), v.end(), 0 ); cout << "sum from " << START << " to " << END << " is " << sum << '\n'; }
The accumulate function can also be used on non-numerical types. The following
example uses accumulate to concatenate all of the strings in a
vector into a single string:
int main () { string str = "Hello World!"; vector<string> vec(10,str); // vec = ["Hello World!", "Hello World!", ...] string a = accumulate( vec.begin(), vec.end(), string("") ); cout << a << endl; // displays "Hello World!Hello World!Hello..." }
Related Topics: adjacent_difference, count, inner_product, partial_sum