Count frequency of a character in an array in C++

#include <iostream>
using namespace std;
int i=0 , n=0 , a[5]={0,0,0,0,0};
int my_function()
{
    if(i<5)
    {
        if(a[i]==0)
        {
            n=n+1;
        }
        i++;
        my_function();
    }
}
int main()
{
    for(i=0;i<5;i++)
    {
        cin>>a[i];
    }
    i=0;
    my_function();
    cout<<"Number of 0 is : "<<n;
}