algo/count1.cpp

The following code example is taken from the book
The C++ Standard Library - A Tutorial and Reference
by Nicolai M. Josuttis, Addison-Wesley, 1999
© Copyright Nicolai M. Josuttis 1999


#include "algostuff.hpp"
using namespace std;

bool isEven (int elem)
{
    return elem % 2 == 0;
}

int main()
{
    vector<int> coll;
    int num;

    INSERT_ELEMENTS(coll,1,9);
    PRINT_ELEMENTS(coll,"coll: ");

    // count and print elements with value 4
    num = count (coll.begin(), coll.end(),       // range
                 4);                             // value
    cout << "number of elements equal to 4:      " << num << endl;

    // count elements with even value
    num = count_if (coll.begin(), coll.end(),    // range
                    isEven);                     // criterion
    cout << "number of elements with even value: " << num << endl;

    // count elements that are greater than value 4
    num = count_if (coll.begin(), coll.end(),    // range
                    bind2nd(greater<int>(),4));  // criterion
    cout << "number of elements greater than 4:  " << num << endl;
}