Standard C++ Library Class Reference

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count, count_if

Algorithm

Summary

Count the number of elements in a container that satisfy a given condition.

Contents

Synopsis●

Description●

Complexity●

Example●

Warnings●

Synopsis

#include <algorithm>

template <class InputIterator, class T, class Size>

void count(InputIterator first, InputIterator last,

const T& value, Size& n);

template <class InputIterator, class Predicate, class Size>

void count_if(InputIterator first, InputIterator last,

Predicate pred, Size& n);

Description

The count algorithm compares value to elements in the sequence defined by iterators first and

last, and increments a counting value n each time it finds a match. i.e., count adds to n the

number of iterators i in the range [first, last) for which the following condition holds: