Frequency of each Character in Array .cpp

// Method -1 (Basic)

#include <bits/stdc++.h>
using namespace std;
 
#define SIZE 26
 
// function to print the character and its frequency
// in order of its occurrence
void printCharWithFreq(string str)
{
    // size of the string 'str'
    int n = str.size();
 
    // 'freq[]' implemented as hash table
    int freq[SIZE];
 
    // initialize all elements of freq[] to 0
    memset(freq, 0, sizeof(freq));
 
    // accumulate freqeuncy of each character in 'str'
    for (int i = 0; i < n; i++)
        freq[str[i] - 'a']++;
 
    // traverse 'str' from left to right
    for (int i = 0; i < n; i++) {
 
        // if frequency of character str[i] is not
        // equal to 0
        if (freq[str[i] - 'a'] != 0) {
 
            // print the character along with its
            // frequency
            cout << str[i] << freq[str[i] - 'a'] << " ";
 
            // update frequency of str[i] to 0 so 
            // that the same character is not printed 
            // again
            freq[str[i] - 'a'] = 0;
        }
    }
}
 
int main()
{
    string str ;
    getline(cin,str);
    printCharWithFreq(str);
    return 0;
}


//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Method -2 (Efficient -Using Hashing)

#include <bits/stdc++.h>
using namespace std;
 
void prCharWithFreq(string s)
{
  // Store all characters and 
  // their frequencies in dictionary
  unordered_map<char, int> d;
 
  for(char i : s)
  {
    d[i]++;
  }
 
  // Print characters and their 
  // frequencies in same order 
  // of their appearance
  for(char i : s)
  {
    // Print only if this 
    // character is not printed
    // before
    if(d[i] != 0)
    {
      cout << i << d[i] << " ";
      d[i] = 0;
    }
  }
}
  
// Driver Code
int main()
{
  string str ;
  getline(cin,str);
  prCharWithFreq(s);
}