11.11 Numeric Algorithms This sect

11.11 Numeric Algorithms

This section presents the STL algorithms that are provided for numeric processing. However, you
can process other than numeric values. For example, you can use accumulate() to process the sum
of several strings. To use the numeric algorithms, you have to include the header file :
#include

11.11.1 Processing Results

Computing the Result of One Sequence

T
accumulate (InputIterator beg, InputIterator end,
T initValue)

T
accumulate (InputIterator beg, InputIterator end,
T initValue, BinaryFunc op)

• The first form computes and returns the sum of initValue and all elements in the range [beg,end).
In particular, it calls the following for each element:
initValue = initValue + elem

• The second form computes and returns the result of calling op for initValue and all elements in
the range [beg,end). In particular, it calls the following for each element:
initValue = op (initValue ,elem)

• Thus, for the values
a1 a2 a3 a4 ...
they compute and return either
initValue + a1 + a2 + a3 + ...
or
initValue op a1 op a2 op a3 op ...
respectively.
• If the range is empty (beg==end), both forms return initValue.
• op must not modify the passed arguments.
• Complexity: linear (numElems calls of operator + or op (), respectively).

The following program demonstrates how to use accumulate() to process the sum and the product
of all elements of a range:

// algo/accumulate1.cpp

#include "algostuff.hpp"
using namespace std;