# Frequency of each character in a String using unordered_map in C++

Given a string str, the task is to find the frequency of each character of a string using an unordered_map in C++ STL.

Examples:

Input: str = “geeksforgeeks”
Output:
r 1
e 4
s 2
g 2
k 2
f 1
o 1

Input: str = “programming”
Output:
n 1
i 1
p 1
o 1
r 2
a 1
g 2
m 2

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach:

1. Traverse each character of the given string str.
2. Check whether the current character is present in unordered_map or not.
3. If it is present, then update the frequency of the current characters else insert the characters with frequency 1 as shown below:
```if(M.find(s[i])!=M.end()) {
M.insert(make_pair{s[i], 1});
}
else {
M[s[i]]++;
}
```
4. Traverse the unordered_map and print the frequency of each characters stored as a mapped value.

Below is the implementation of the above approach:

 `// C++ program for the above approach ` ` `  `#include ` `using` `namespace` `std; ` ` `  `void` `printFrequency(string str) ` `{ ` `    ``// Define an unordered_map ` `    ``unordered_map<``char``, ``int``> M; ` ` `  `    ``// Traverse string str check if ` `    ``// current character is present ` `    ``// or not ` `    ``for` `(``int` `i = 0; str[i]; i++) { ` ` `  `        ``// If the current characters ` `        ``// is not found then insert ` `        ``// current characters with ` `        ``// frequency 1 ` `        ``if` `(M.find(str[i]) == M.end()) { ` `            ``M.insert(make_pair(str[i], 1)); ` `        ``} ` ` `  `        ``// Else update the frequency ` `        ``else` `{ ` `            ``M[str[i]]++; ` `        ``} ` `    ``} ` ` `  `    ``// Traverse the map to print the ` `    ``// frequency ` `    ``for` `(``auto``& it : M) { ` `        ``cout << it.first << ``' '` `             ``<< it.second << ``'\n'``; ` `    ``} ` `} ` ` `  `// Driver Code ` `int` `main() ` `{ ` `    ``string str = ``"geeksforgeeks"``; ` ` `  `    ``// Function call ` `    ``printFrequency(str); ` `    ``return` `0; ` `} `

Output:

```r 1
e 4
s 2
g 2
k 2
f 1
o 1
```

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