How to print unique characters of a string in C++?

In this C++ tutorial, you shall learn how to get and print the unique characters of a given string using Set collection, with example programs.

Print Unique Characters of a String

To print unique characters of a string in C++, iterate over the characters of the string, insert each of the character in a set, and print them.

C++ Program

In the following program, we include set library so that we can use Set collection. We take a string in str variable, and print the unique characters in this string to console.

main.cpp

#include <iostream>
#include <set>
using namespace std;

int main() {
   string str = "apple";
   set<char> uniqueChars;

   //insert characters in set
   for(char& ch : str) {
      uniqueChars.insert(ch);
   }

   //print unique characters
   for(auto ch : uniqueChars) {
      cout << ch << endl;
   }
}

Output

a
e
l
p

Reference

In the above program(s), we have used the following C++ concepts. The links have been provided for reference.

• C++ Foreach loop

Conclusion

In this C++ Tutorial, we learned how to print unique characters of a given string.