CPP

count function vector c++

// CPP program to count vector elements that
// match given target value.
#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;
  
int main()
{
    vector<int> v{ 10, 30, 30, 10, 30, 30 };
    int target = 30;
    int res = count(v.begin(), v.end(), target);
    cout << "Target: " << target << " Count : " << res << endl;
    return 0;
}

c++ count number of element in vector

count(vect.begin(), vect.end(), 3)

c++ count vector elements

// 1.
for(std::vector<int>::iterator it = vector.begin(); it != vector.end(); ++it)
    sum_of_elems += *it;

// 2.
// #include <numeric>
sum_of_elems = std::accumulate(vector.begin(), vector.end(), 0);

// C++11 and higher
// 3.
// #include <numeric>
sum_of_elems = std::accumulate(vector.begin(), vector.end(),
                               decltype(vector)::value_type(0));

// 4.
for (auto& n : vector)
    sum_of_elems += n;