# Find the frequency of each element in an array in c++

C++ program for Find the frequency of each element in an array. Here problem description and explanation.

``````// Include header file
#include <iostream>
#include <unordered_map>
using namespace std;
class Occurrence
{
public:
// Function which is display array elements
void display(int arr[], int n)
{
for (int i = 0; i < n; ++i)
{
cout << "   " << arr[i];
}
cout << "\n";
}
// Count occurrence of given array
void frequency(int arr[], int n)
{
// Display given array
this->display(arr, n);
// Create a empty map
unordered_map < int, int > map;
for (int i = 0; i < n; i++)
{
if (map.find(arr[i]) != map.end())
{
// When key exists then update value
map[arr[i]] = map[arr[i]] + 1;
}
else
{
map[arr[i]] = 1;
}
}
cout << "  Occurrence " << endl;
//  Display calculated result
for (auto &key: map)
{
cout << "  " << key.first << "  :  "
<< map[key.first] << endl;
}
}
};
int main()
{
// Array element
int arr[] = {
1 , 3 , 2 , 1 , 4 , 2 , 7 , 9 , 1 , 3 , 3 , 4 , 7
};
int n = sizeof(arr) / sizeof(arr);
return 0;
}``````

Output

``````   1   3   2   1   4   2   7   9   1   3   3   4   7
Occurrence
9  :  1
7  :  2
1  :  3
3  :  3
2  :  2
4  :  2``````

Please share your knowledge to improve code and content standard. Also submit your doubts, and test case. We improve by your feedback. We will try to resolve your query as soon as possible.

### New Comment 