Second Frequently Occurring Number in C++

Hey there!

Question: Print the second frequently occurring number.

So, there are several method to achieve this, in this article we’ll see two method.

Solution 1:

#include<iostream>
#include<string>
using namespace std;
int repeat(int arr[],int n){
  int max1=0, max2=0, count[256]={0};
  
  for(int i=0; i<n; i++){
    count[ arr[i] ]++;
  }
// or change function type to char and (count [ '0' + a[i] ]++)
  
  for(int i=0; i<256; i++){
    if(count[i] > count[max1]){
      max2 = max1;
      max1 = i;
    }
    else if( count[i] > count[max2] && count[i] != count[max1] ){
      max2 = i;
    }
  }
  return max2;
}
int main() {
  int arr[] = {3,2,2,3,4,4,4,8,8,8,8,9,8};
  int n = sizeof(arr)/sizeof(arr[0]);
  cout << repeat(arr,n);
}

Solution 2:

#include<iostream>
#include<bits/stdc++.h>
using namespace std;
int secondFrequent(int num){
  int count;
  map<int, int> indi_num;
  while(num > 0){
    indi_num[(num%10)]++;
    num /= 10;
  }
  map<int, int>::iterator m;
  int max1=0, max2=0, first_num, second_num;
  for(m = indi_num.begin(); m != indi_num.end(); m++){
    if(m->second > max1){
      max2 = max1;
      max1 = m->second;
      second_num = first_num;
      first_num = m -> first;
    }
    else if( m->second > max2){
      max2 = m->second;
      second_num = m->first;
    }
    //cout << m->first << " " << m-> second << endl;
  }
  return second_num;
}
int main(){
  int num = 1123124;
  cout << secondFrequent(num);
}

Please let me know if you have any other approach to this problem.

Thanks!