STL Question (frequency)

[Eibro]

Is there any algorithm included in the STL which allows you to find the frequency (or "mode") of an element in one of the standard containers? I couldn't find any info in the reference; perhaps I was searching for the wrong name.

Thanks in advance.

[Brighteyes]

What about count or count_if?

#include <algorithm>
#include <iostream>
#include <vector>

using namespace std;

int main()
{
    int list[] = {1,2,3,3,1,2,3,5,4,3,2,4,2,3,1};
    vector<int> vlist(list, list + 15);
    
    vector<int>::difference_type n(count(vlist.begin(), vlist.end(), 3));
    cout<<"There are "<< n <<" 3's in vlist"<<endl;
    
    cin.get();
}

[Sang-drax]

With frequency, do you mean number of occurrences? (I'm not sure what "mode" means in this context)

If so, use the count algorithm:

vector<int> vec = ....
...
//Obtain the frequency of 2
cout << count(vec.begin(),vec.end(),2);

[Eibro]

Originally posted by Sang-drax
With frequency, do you mean number of occurrences? (I'm not sure what "mode" means in this context)

If so, use the count algorithm:

vector<int> vec = ....
...
//Obtain the frequency of 2
cout << count(vec.begin(),vec.end(),2);

Yes, number of occourences. Thanks to you both for the help.